What we know
10:30pm: Students sitting exams disrupted by the quakes are calling for leniency and demanding an apology from NZQA over its handling of the cancellations and postponements.
"NZQA's late action disadvantaged students as we were unsure whether exams would go ahead, consequently filling us with additional (and unneeded) stress and anxiety," a petition on change.org claims.
10:20pm: The cricket Test between New Zealand and Pakistan in Christchurch will go ahead, after engineers confirmed Hagley Oval's fine. The Pakistan team were shaken up by the midnight movements though.
9:55pm: Dr Chris Brown of Bondi Vet fame has taken an interest in the cows stranded on a quake-formed atoll near Kaikoura.
9:30pm: Train services in Palmerston North and north of the city are open, as is the midland line between Rolleston and Greymouth.
Services have been disrupted due to the quake, with lines covered by slips or split completely.
The North Island main trunk line south of Palmerston North remains shut Monday night, while engineers inspect it.
There still aren't any passenger services in Wellington, but KiwiRail hopes to have them back up and running before rush hour on Tuesday.
The main north line between Picton and Christchurch has "significant damage", particularly around Kaikoura, which aerial footage shot earlier today shows is covered in slips.
Interislander ferries are back up and running, but only carrying vehicle passengers and freight, thanks to damage to the Picton ferry terminal.
9:20pm: Victoria University students hoping for a day off on Tuesday are out of luck - the Kelburn and Te Aro campuses have been checked and given the all-clear, while the Pipitea and Karorio campuses are expected to follow during the day.
"While the earthquakes have been frightening for both staff and students, I am very pleased to confirm that no injuries have been reported," says vice-chancellor Grant Guilford.
Victoria's offering accommodation to students who need a place to stay - doesn't matter which uni they go to.
"We accommodated over 100 displaced students and neighbours at one of our halls of residence, Te Puni Village, in the hours after the earthquake. Many were international students who had been evacuated from their apartments.
"We are able to provide beds, food, warmth and company and are happy to do the same for any other tertiary students in Wellington who need temporary lodgings."
9:10pm: An alternative route between Picton and Christchurch has been established, going via Murchison and the Lewis Pass.
Parts of it will only be a single lane however, says NZTA, and motorists are urged to take caution.
State Highway 1 from Picton to Blenheim and Seddon is now open, but Seddon to Cheviot remains closed.
Highway manager Neil Walker says the priority is connecting cut-off communities, like Kaikoura.
"Transport Agency and council teams are working as fast as we can to reopen highways or find alternative routes."
State Highway 7A to Hanmer Springs remains closed due to fear of rockfalls. It will reopen at 7am, but to light vehicles only.
Further updates are available on the NZTA website, or on 0800 44 44 49.
Lynda Murchison from North Canterbury Federated Farmers says there's been little word so far from stranded areas.
She says any farmer who needs help should phone the Federated Farmers helpline on 0800 FARMING.
8:55pm: A Dutch tourist in Kaikoura says he's had "the strangest night in my entire life".
He was waiting for a nice day to go hiking, but the earthquake intervened.
"As quick as we can we packed some stuff and drove to higher grounds, because we were really near the sea," he told Newshub.
"Driving over the hill on the main highway in Kaikoura, I had to brake hard to avoid ending up in a massive crack that had formed.
"I noticed that there was a campervan stuck on it. Turned around we found a safe spot to stay the night.
"The next morning I went back to the place with the cracked road and saw the owner of the camper inspecting the massive crack that had formed while he drove when the earthquake hit. Quickly I took the chance to take this shot that shows the power and damaging force of the earthquake."
8:30pm: Two strong aftershocks have struck Seddon in the past 15 minutes - one 5.8 at a depth of 23km, the other 5.9 at 15km.
8:15pm: The quake that hit Kaikoura half an hour ago has been downgraded from 6 to 5.7 Meanwhile, a 6.2 shake his hit Argentina, where Prime Minister John Key was due to leave for on Tuesday.
8:05pm: HMNZS Canterbury will support the ongoing response in the Kaikoura region, which has been hardest-hit by the earthquake.
"The Prime Minister and I have now seen first-hand the numerous major slips, which have isolated Kaikoura from the north and south," Mr Brownlee says.
"Our immediate priority is ensuring delivery of clean water, food and other essentials to the residents of Kaikoura and the estimated 1000 tourists in the town."
7:52pm: Another big aftershock has hit Kaikoura, 35km deep. It struck at 7:47pm and was described as "strong" by GeoNet.
7:48pm: A magnitude 5.8 earthquake has shaken the lower North Island, striking 20km east of Seddon. Initial reports put it closer to Wellington.
It hit at 7:43pm, and was 36km deep.
Twitter users described it as a "big wobble", "fairly strong" and a "reasonable shake".
7:19pm: The Ministry of Transport has reported that SH1 has reopened between Picton and Blenheim, but is still closed between Seddon and Cheviot.
7:17pm: The Ministry of Civil Defence has tweeted that power has been restored to Kaikoura and Hanmer Springs.
7:14pm: The HNZMS Canterbury is on its way to the Kaikoura region and may be used to help the 1100 stranded tourists get out of the district. Defence Force planes may also start flying out tourists who are desperate to leave.
7:01pm: Prime Minister John Key has said the cost of repair after today's quakes will be in the billions.
"The slips here are horrendous. You've got to believe it's in the billions of dollars to resolve these issues ... they're huge slips, the Manawatu gorge was a big slip in its own right and there's probably half a dozen of those sitting out there to the north of Kaikoura," he said.
7pm: The Sky Tower will light up in black and white on Monday night "as a mark of solidarity with New Zealand" following the magnitude 7.5 quake that shook the country.
"Most New Zealanders will have friends or family who have been affected by these earthquakes and we're lighting the Sky Tower to show our support for those affected," says acting general manager Matt Ballesty.
He called the Sky Tower, New Zealand's tallest building, a "symbol of love, hope, support and solidarity".
"It's our way of saying we're all thinking about you - the rest of New Zealand is here for you."
6.27pm: KiwiRail is hopeful for Wellington passenger services to resume tomorrow. They released a statement this afternoon saying the electric trains should be tested later today, and it is hoped some passenger services can resume tomorrow in time for morning peak.
6:15pm: The kayakers missing on the Clarence River have been found safe.
6:01pm: An alternative route for traffic to head north to Blenheim will be opening tonight. Neil Walker, Transport Agency highway manager, has said that State highway 7 will be reopening.
He said drivers need to be cautious as the route will be down to a single lane in places.
"This alternative route will take approximately three extra hours, so people need factor in a longer journey time into their travel plans and ensure that they have plenty of fuel, warm clothes, food and water," Mr Walker said.
State Highway 1, Picton to Blenheim/Seddon is now open but Seddon to Cheviot remains closed. Cheviot to Christchurch is open.
5:55pm: HMNZS Canterbury will support the ongoing response in the Kaikoura region, which has been hardest-hit by today’s events. Acting Civil Defence Minister Gerry Brownlee says viewing the region from the air revealed extensive damage to essential connections and basic infrastructure.
"Our immediate priority is ensuring delivery of clean water, food and other essentials to the residents of Kaikoura and the estimated 1000 tourists in the town.
"The roads and railways are things that can be repaired in time but it’s important to think of those who lost their lives today or suffered injuries."
5:52pm: The Ministry of Education has announced that the majority of schools in Wellington, Marlborough and Christchurch will reopen as normal tomorrow.
5:49pm: A spokesman for the CDHB has confirmed they had three patients flown to Christchurch hospital from north Canterbury this afternoon. Two males have been admitted, but did not wish to give details on the nature of their injuries.
The third patient was treated and discharged from the Emergency Department within a matter of hours.
5:08pm: Ten additional police officers from Auckland will be on the ground in Kaikoura tonight, to "support the safety and wellbeing of the community".
NZ police have said these additional officers have been deployed to provide support to the emergency response in the affected areas, as well as assist in general policing duties and community patrols.
5:05pm: The missing 16 rafters on the Clarence River have been found safely clear of this afternoon's breach of the Clarence River. A separate group of six kayaks and associated gear including helmets has also been found along the river, which suggests the kayakers have left the river for higher ground. A search is underway for the kayakers. Anybody who knows of the kayakers are asked to contact (03) 520-8400
4:57pm: The dam caused by a slip on north Canterbury's Clarence River has breached and a large wall of water is heading downstream.
16 rafters are unaccounted for on the flooded Clarence River, according to the Malborough District Council.
Civil Defence has urged residents to move to higher ground immediately. They expect it to take around three to five hours for the water to travel 50km down the river from the dam to the coast.
Water had been banking up behind the slip, about 10 to 12 kms upriver from the mouth, and broke through the dammed-up debris at about 4:20pm. Crews are already on their way to the Clarence area.
4:55pm: A spokesperson for the Interislander ferry has said that ferry services for vehicle passengers and freight will resume tonight from 6pm. Foot passangers will not be able to sail due to damage to the Picton terminal.
4:44pm: Police have received 19 reports of burglaries at Canterbury addresses since midnight.
4:13pm: Red Cross has launched an emergency appeal to support communities affected by the quakes. People can donate to Red Cross’ November 2016 Earthquake Appeal at redcross.org.nz/donate/.
3:50pm: Prime Minister John Key has said that the damage to the Kaikoura region is worse than he thought, after flying over in a Defence Force plane.
"It's just utter devastation, I just don't know...that's months of work," John Key told Gerry Brownlee and pilots.
Mr Key and Brownlee have estimated the clean up will run into the hundreds of millions and clearing the debris and blocked roads could take months.
3:46pm: The fire service have tweeted that an urban search and rescue team of 20 people and two dogs has now arrived in Kaikoura. Another team of 20 people is on standby in Christchurch.
3:35pm: Wellington City Council is asking all Wellingtonians to check and secure any cracked or broken glass around their homes, and secure any loose items including trampolines while it is still light.
A severe weather warning is in place for the region with high winds of up to 140kmh, rain and thunder forecast for Monday evening.
"Winds of this strength could lift roofs, damage trees and cause hazardous driving conditions", MetService has warned.
3:33pm: North Canterbury's Clarence River community is being evacuated as a precautionary measure due to slips affecting the river flow.
A slip has blocked the river in the vicinity of the Dart Stream, with a lake already forming behind the blockage.
Manager of Nelson/Marlborough Fish and Game Rhys Barrier has said "there could be a dangerous surge down the river” if the build up of water suddenly breaks through.
3:22pm: The Kaikoura District Council has declared a local state of emergency following the 7.5 magnitude earthquake this morning.
The tsunami risk was lifted earlier this morning, but people are being told to stay away from the coast as a precaution.
There is extensive damage to SH1 north and south of Kaikoura.
3:19pm: The Waikato District Council is asking Raglan residents to conserve and boil their water as a precaution after this afternoon’s aftershocks.
They've said the spring that supplies the water to the treatment plant is discoloured.
The council have warned that if “disruption to the spring continues, there is a real risk of running out of water in Raglan”. They recommend residents only use water for drinking at this time.
3:15pm: Australian Prime Minister Malcolm Turnbull has spoken to Prime Minister John Key and offered New Zealand "absolute solidarity and support".
"We support the Kiwis and they support us when it comes to national emergencies and disasters like this."
Mr Turnbull says Mr Key told him his office in Wellington shook, with furniture being knocked over and plates thrown out of cupboards.
3:10pm: The missing truck driver in Kaikoura has been found safe. He called his company this afternoon to let them know of his location.
3:01pm: Nelson and Marlborough Fish & Game have told anglers to avoid North Canterbury's Clarence River downstream of the gorge.
2:55pm: United States Secretary of State John Kerry has spoken on the phone with New Zealand Foreign Minister Murray McCully to offer condolences for the loss of life in today's quake. He also wished well all those who suffered injuries. The Secretary praised the skill of New Zealand's first responders and dedicated medical professionals, who reacted so quickly, and he offered whatever U.S. assistance might be required.
2:53pm: Wellington Airport is open, with only minimal damage to the car park, but flights could still be delayed because of bad weather.
Airport spokesman Greg Thomas says an immediate inspection revealed no damage and the airport was operational half an hour later.
There was no damage to the terminal building or air bridges, but the multi-level carpark which is currently under construction was damaged.
Most flights are running on time, but there may be a few delays or changes.
2:18pm: The colleagues of a missing truck driver are worried his truck is buried under a landslide on the Kaikoura coast. He was last seen headed North on the road 10 minutes before the quake and he has not been heard from since.
His colleague Rangi Dellaway says they notified Civil Defence straight away, but haven't heard if searchers have found the man yet. "You don't know if he's parked up or at someone's house, but we need a call. It would be good to hear from him," says Mr Dellaway. "I hope he's just talking to a local, wihtout any power or phone reception." However, Mr Dellaway says they are fearing the worst, as the "treacherous piece of road" gives away very easily. "It's happened before," he says.
The registration number of the missing vehicle is DKT420 and its name is Black Spirit.
A truck identical to the one missing on Kaikoura coast (Newshub).
2:15pm: KiwiRail chief executive Peter Reidy says it could be two days before they know the extent of the damage to the local rail network, ut first impressions suggest it's at least on the same scale as the Christchurch quakes of 2010 and 2011.
2pm: Civil Defence says there's no tsunami threat following the two big aftershocks in the South Island.
Canterbury District Health Board has said their health services across Canterbury and the West Coast are operating normally, and for most people their GP should be the first point of call for non-emergency care.
1:30pm: Two large aftershocks have just hit North Canterbury, including a 6.3 located 30km north of Cheviot.
1pm: Two of NZ's major network providers are helping friends and family keep in touch with some freebies.
Spark have said "To help all New Zealanders stay in touch with friends and family today following the earthquake, Spark is letting anyone use our nationwide Wi-Fi network, without restrictions on data limits or who can use it, for free. Once you are within range of a Spark Wi-Fi hotspot, simply search for the Spark network (named ‘Spark Wi-Fi zone’) and click to join the network. There will be no need to register or enter log-in details to get online."
2degrees have said "In response to this morning’s earthquake 2degrees customers will not be charged for national SMS messages today (from 12am). We encourage people to text rather than call".
12:56pm: Hurunui Mayor Winton Dalley declares an official 'State of Emergency' in the Hurunui district. 12,000 people live in the district that's around 120 kilometres south west of Kaikoura.
12:40pm: Reports of a person trapped in a landslide in Ohau, north of Kaikoura, after the 7.5 mag quake this morning
11:45am: The stranded Kaiarahi ferry has now berthed in Picton and is unloading its passengers, following earthquake damage at Picton and Wellington ports.
10:23am: The aftershocks don't seem to be dying down in frequency, but they are definitely becoming less intense. The last aftershock that was more than a magnitude-5 struck in Kaikoura well over two hours ago.
10:04am: Police advising people to remain away from buildings in the affected areas - especially those with large numbers of glass or masonry.
9:55am: Drinking water in Christchurch gets the go-ahead from the council.
9:49am: St John say they've yet to receive any more reports of injuries or deaths as a result of the tremors overnight.
9:38am: Earlier, structural engineers discovered that the BNZ Centre had been seriously damaged - here's a little snippet of that from Newshub reporter Alex Baird.
9:28am: The latest update from Civil Defence reveals that reports of damaged buildings have come from a number of regions, including Canterbury, Wellington and Blenheim. There's also extensive damage inflicted on bridges along State Highway 1.
9:15am: Things going from bad to worse in Wellington. After a number of hefty aftershocks in the capital, the council has revealed that a lot of structural damage has been done to buildings, and that 140km/h winds are expected today.
9:13am: Bluebridge joins Interislander in suspending all its ferry trips until further notice.
9:10am: The NZQA has announced that all its NCEA Scholarship exams have been postponed.
9:06am: Samantha Hayes and Tom McRae are leading the coverage of the quake now, taking over from Paul Henry. Watch live coverage of what's going on around the country here.
9:02am: Raglan locals have been advised to conserve water due to disruptions in the water supply.
8:53am: Wellingtonians living in 'unsafe accommodation' seek refuge in the foyer of Parliament this morning. Only in New Zealand.
8:45am: Despite the tsunami warning no longer being in place, locals from Napier to north of Dunedin and Chatham Island have been told not to go near the coast, as a marine and beach threat remains in place.
8:35am: Fresh cracks in the road proving a surprise to Wellington locals.
8:30am: In a surprising turn, GeoNet are now reporting that the one 7.5-magnitude quake may well have been two earthquakes, which would explain why the aftershocks have been felt so far from the epicentre.
8:21am: Seddon is also getting a battering - GeoNet just reported that the town had felt four aftershocks in four minutes. This was the worst of them. The two areas between them would have had close to 100 aftershocks by now.
8:13am: Kaikoura still getting absolutely bombarded with aftershocks. The coastal town has just been given another rude shake, this time a magnitude-5.6.
8:10am: Civil Defence has downgraded its tsunami warning again. There's now no waves expected more than one-metre high.
7:51am: A big crack at Wellington Port (Ben Irwin/Newshub.)
7:40am: Rockfall between Rotherham to Waiau.
7:35am: The Education Ministry is advising schools from North Canterbury to Wellington not to open until the buildings can be checked.
7:32am: A train has been stopped near Kaikoura as a precaution. The driver is safe and will remain there for the time being.
7:29am: Aftershocks continue to strike every one or two minutes, mostly centred in the area from Seddon to Cheviot.
7:21am: The person who died in Mt Lyford died from a cardiac arrest.
7:18am: The Qualifications Authority says NCEA exams in most parts of the country will continue but students unable to attend will be given assessed grades. More info here.
7:15am: These is still a tsunami threat to Chatham Islands and the coast between Blenheim and Banks Peninsula.
7:04am: CCTV footage shows the moment the quake struck Fresh Choice supermarket in Nelson.
6:58am: Current tsunami threat levels
6:51am: A military helicopter has been sent to Kaikoura.
6:50am: Key says Kaikoura is cut off by road.
6:49am: Prime Minister John Key says he has no indication the death toll will rise from two. One of the deaths was at the Elms Homestead in Kaikoura and another at Mt Lyford, east of Hanmer Springs.
6:45am: All scheduled sailings due to depart Queens Wharf, Days Bay and Seatoun this morning have been cancelled due to Earthquake damage and tsunami risk. There will be no replacement shuttles as they are unavailable due to road damage.
6:41am: Damage in Wellington
6:31: The tsunami warning has been downgraded significantly. People in green and white areas can go home.
6:17am: State Highway One in the Hundalees (Photos: Annabelle Tukia/Newshub)
6:14am: The tsunami warning has been lifted south of Banks Peninsula.
6:12am: All Hawke's Bay residents are now cleared to go home but they must stay off the beaches.
5:59am: Two deaths have been confirmed, one in Kaikoura at a collapsed building and one in Mt Lyford, east of Hanmer Springs.
5:49am: Live stream of Lyall Bay shows empty streets.
5:43am: A full update for people in the Marlborough area, including emergency centres, here
5:42am: Cook Strait ferries are cancelled all day.
5:38am: The Fire Service say TSB Arena and BNZ Centre on Wellington's waterfront have sustained the most damage.
5:36am: Instagram user 'Syrian Kiwi' caught this phenomenal footage of lights flashing in the sky over Wellington as the quake struck.
5:28am: Wellington Civil Defence is advising people not to go into the CBD today. People in Lower Hutt should check with their employer before going to work.
5:22am: St John said they have not confirmed a death a death in Christchurch, despite media reports.
5:14am: Some good news - no reports of damage in Cheviot - the epicentre.
5:06am: The threat of tsunamis remains with warnings of up to five metres along the East Coast and hundreds of people have been evacuated.
5:03am: All airports remain open.
4:47am: There are reports of casualties in Kaikoura, Canterbury Earthquake Recovery Minister Gerry Brownlee says. Communications are disrupted and few details are available.
"There are some reports of casualties in the Kaikoura area but the extent of that is not yet reported."
4:40am: The earthquake and tsunami response is being managed by local authorities. Find your local Civil Defence group here
4:36am: Damage at New World Blenheim (Ross Wearing)
4:32am: The aftershocks continue to roll in every one to two minutes.
4:29am: The Gisborne District Council has lifted the tsunami warning for the Gisborne coast.
4:20am: Passengers are having to sleep onboard an Interislander ferry stranded in the Cook Strait.
4:16am: The 111 service is back up-and-running and people are urged to use it if they are experiencing an emergency.
4:13am: Tsunami waves ar being recorded in Kaikoura and parts of Wellington.
4:09am: A number of paramedics are being sent to North Canterbury after reports of injuries from this morning's severe quake in Canterbury.
4:06am: The tsunami warning remains in effect.
4:02am: State Highway One near Cheviot.
3:59am: Evacuations are continuing in the eastern suburbs of Christchurch and all beaches/coastal communities in North Canterbury.
3:57am: Ferry sailings in the Cook Strait are cancelled until a full assessment can be made in the daylight.
3:56am: All trains in the South Island and all trains on the North Island main trunk line south of Palmerston North are cancelled until further notice.
3:56am: Waiau, only a few kilometres from the original epicentre in Cheviot, has power and phone lines down. There are also reports not all residents in the area have been accounted for yet.
3:54am: North Canterbury towns Rotherham and Waiau are still cut off by slips and extensive damage to the bridge.
3:54am: North Canterbury residents are being urged to boil drinking water as a precaution.
3:48am: The centre of the road at Homestead Gully, half an hour north of Cheviot.
3:34am: Huge boulders on Leader Rd, off SH1 at Hawkswood, north of Cheviot.
3:32am: Large cracks on Leader Rd, off SH1 at Hawkswood, north of Cheviot.
3:30am: Dunedin City Council has declared a State of Emergency.
3:29am: People pour onto the streets on Manners St in Wellington.
3:28am: Mannequins down on Cuba St.
3:26am: For those who are travelling to higher ground, there may be more traffic on the roads. Please exercise tolerance and patience.
3:25am: The New Zealand Transport Agency says people should people delay travel on State Highway 1 between Picton to Christchurch.
3:18am: Civil Defence says waves up to five metres are possible between Marlborough and Banks Peninsula. There is a threat to the entire New Zealand coast and everyone is warned to stay off beaches.
3:16am: Boulders have come down on the Lewis Pass near the Hurunui Bridge.
3:15am: Reports traffic is gridlocked in the Christchurch suburbs of Linwood and Ferrymead as people head inland.
3:13am: Police are now helping with evacuations in eastern Christchurch and instructing people to move to higher ground.
3:03am: The video above is from Code Club Aotearoa.
3:02am: A line of cars heading west out of Christchurch.
3:01am: The tsunami sirens in Sumner have stopped going off but people are still waiting up the hill.
2:53am: State Highway One at Waipara, north of Christchurch, is reportedly covered in boulders.
2:49am: Damage to State Highway One near Cheviot.
2:38am: Damage to the Interislander drawbridge in Wellington.
2:36am: Four people are being transferred to Christchurch hospital from Mt Vernon Lodge in Akaroa. Their injuries are unknown.
2:34:am: The Wellington newsroom
2:31am: Two people have been injured after the Kaikoura Elms Homestead collapsed.
2:29am: There are reports one person is trapped under a wine tanker at Cloudy Bay near Blenheim.
2:27am: Hundreds of Christchurch residents living in coastal areas are evacuating their properties. Police are at the bottom of the hills in and around Cashmere urging residents to go up to higher ground.
2:20am: Another strong quake has been felt in Wellington.
2:18am: There are reports people are running for the hills as the water recedes in Lyall Bay, Wellington.
2:08am: Damage to buildings on Wakefield Street, Wellington.
2:07am: There are unconfirmed reports the Aratere Ferry is stranded in Wellington Harbour.
2:03am: GeoNet has revised the size of the initial quake upwards to magnitude 7.5.
2:01am: Damage in Wellington:
1:57am: The 111 service is back up and running.
1:53am: There are reports on Facebook there has been a two metre tsunami in Kaikoura.
1:48am: There are reports a rail bridge near Wellington Stadium and the Ferry terminal in Wellington has collapsed.
1:44am: Prime Minister John key is being briefed and the emergency bunker has been activated.
1:44am: Structural engineers have hit the streets of Wellington.
1:40am: Mass evacuations are taking place from coastal settlements in Canterbury after a tsunami warning.
1:37am: The Ambulance Service is reporting a building has collapsed on State Highway One in Kaikoura.
1:35am: The tsunami warning area has been extended to the Eastern Coast of the North Island and South Island and southern area of the South Island.
1:33am: There are reportedly one metre cracks in the road south of Kaikoura.
1:30am: Quakes are continuing to strike up and down the country around every minute.
1:28am: The damage at Fresh Choice supermarket in Nelson.
1:10am: A tsunami warning has been issued to all southern areas of New Zealand.
The Ministry of Civil Defence and Emergency Management (MCDEM) says that the first wave of activity may not necessarily be the most significant and it may continue for several hours. Civil Defence is urging residents to regard the warning as real until cancelled.
A tsunami warning has been issued after a series of severe earthquakes struck the South Island.