This article is no longer being updated. The latest updates can be found here.
Around 50 people were on White Island when it erupted on Monday afternoon and many remain unaccounted for.
The volcanic eruption began at around 2:11pm, GNS says.
Police have confirmed five people are dead. St John confirmed there are several serious injuries.
What you need to know:
- The eruption began at 2:11pm on Monday afternoon
- Volcanologists have confirmed it was the biggest eruption in recent history
- Five people are confirmed dead
- Up to 50 people may have been on the island when it erupted
- The injured have been taken to Whakatane and Middlemore Hospitals, many with burns
- NZDF assets and personnel are being sent to assist the emergency response
- Watch the press conference detailing the latest updates here
These live updates have now ended.
9:30pm - A number has been set up so the friends and family of those involved can make contact with the police.
People within New Zealand can call 105 or get in contact through the police website.
A number for people overseas will be provided shortly.
The Red Cross has activated the Family Links website so people can register themselves as safe or submit an inquiry about a loved one.
"Our thoughts are absolutely with the friends and family."
9:16pm - A number of people have been taken to Whakatane and Middlemore Hospitals, many suffering from burns. It is still too early for police to confirm how many were involved.
"We believe a number of these tourists have come from the Ovation of the Seas cruise ship," Tims said.
Tims said he couldn't comment on reports of "more than 20" Australians being on the island at the time of the eruption.
9:14pm - Tims said police are "unsure" of the wellbeing of those on the island. They remain uncertain of the exact number of people remaining on the volcano.
"We're working with a range of people to identify the numbers and names of those on the island and who have visited the island. It takes time. We have to make sure we have the right information.
"Experts say it is unsafe for us to go onto the island."
Tims confirmed the deceased are from "a range" of nationalities, but they are unconfirmed.
9:11pm - Five people who were rescued earlier on Monday have died, police confirmed.
The physical environment on White Island remains too unsafe for rescuers and emergency services to return. It is currently a no-fly zone.
8:57pm - The Defence Force has released a statement confirming a number of NZDF assets and personnel are being sent to assist in the emergency response.
"The NZDF will be working under the direction of NZ Police but has sent a number of assets to the area to help as needed.
"A Royal New Zealand Air Force P-3K2 Orion aircraft has flown over White Island carrying out surveillance over the area, and two NH90 helicopters have flown to Whakatane to assist.
"Royal New Zealand Navy ship HMNZS Wellington is currently transiting from Auckland to Whakatane to offer support.
"Our thoughts are with everyone affected."
8:45pm - Police deputy commissioner John Tims will be providing updates at Police National Headquarters in a second press conference. It is expected to begin at 9pm. Watch the livestream here.
8:30pm - A Royal Caribbean spokesperson told Newshub:
"We can confirm that a number of our guests were touring the island today. We do not have any additional details to share at this time.
"Ovation of the Seas will remain overnight until we learn more about the situation. We will offer all possible assistance to our guests and local authorities.
"Please keep all those affected in your prayers."
8:23pm - 7 News reports "more than 20 Australians were on the island when the volcano erupted".
8:10pm - Twenty-four Australians were understood to be on the island at the time of the eruption, according to Scott Morrison's office.
8:02pm - The Prime Minister of Australia, Scott Morrison, said he has offered "full support" to Ardern following the eruption.
Morrison said Australians have been caught up in the "terrible tragedy" and their wellbeing is yet to be determined.
7:35pm - Photos taken by Michael Schade show White Island Tour operators rescuing people from the volcano.
7:20pm - Ardern and Minister for Civil Defens, Peeni Henare, will travel to the area on Monday evening.
7:13pm - Footage shows an abandoned helicopter on White Island.
7:06pm - Police said both New Zealanders and overseas tourists are believed to be involved.
"The island is currently covered in ash and we are taking expert advice with regards to the conditions to determine when we can safely access the island," a police spokesperson says.
They recommend people continue visiting the Civil Defence and Emergency Management website for safety advise.
7:00pm - Waikato Hospital asks people to stay away unless it's an emergency.
A number of people have been transported to Whakatane Hospital and Middlemore Hospital, some with critical injuries.
6:47pm - Authorities believe more deaths are likely.
Tims said most of the injured have experienced burns.
GNS Science technical advisor Ken Gledhill said they "can't be certain" there won't be another eruption in the next 24 hours.
6:40pm - Tims told media there should be a list of people that left the cruise ship and were potentially on the island at the time of the eruption. The cruise ship Ovation of the Seas berthed at the Port of Tauranga on Monday morning.
Prime Minister Jacinda Ardern said the ash is making it difficult to see what is happening on White Island through GNS cameras.
6:36pm - Authorities confirmed 23 people have been rescued. A number still remain unaccounted for. Fewer than 50 were on the volcano at the time of the eruption.
Tims said it is too dangerous for rescue services and police to go to the Island and they will continue to monitor the conditions.
"At this stage, it is too dangerous for police and emergency services to go on the island... we will provide more details as they come to hand."
6:30pm - National operation commander, deputy commissioner John Tims confirmed one person died when White Island erupted on Monday afternoon.
More deaths are likely, according to police information.
Tims, Prime Minister Jacinda Ardern and Sarah Stuart-Black, director of Civil Defence Emergency Management Groups, have spoken to media at a press conference shortly after 6:30pm.
6:10pm - Deputy Prime Minister Winston Peters has expressed his "deep sympathy" to all those grieving from the news coming from White Island.
6pm - The New Zealand Cruise Association is "very concerned" that passengers from the Ovation of the Seas cruise ship were on the island at the time of the eruption.
"Our primary concern right now is with the wellbeing of the passengers and all those involved. We would like to extend our heartfelt concern to the passengers and their families," NZCA chief executive officer Kevin O'Sullivan says.
"Our hope is that everyone will be recovered quickly and unharmed, but at this time we have no further information."
5:55pm - Labour MP Tamati Coffey is outside White Island Tours in Whakatāne.
"Needless to say it's pretty emotional there are people who are in tears - there's an element of people in shell shock," he says.
"Somebody just relayed to me that as they were getting on the boat to leave. They got to leave but the people on the boat behind them perhaps weren't quite so lucky.
"There's talk about burns - the details are quite sketchy at the moment… the mood is incredibly sombre, lots of hugging and crying.
"It's still very real - it's still unfolding. I don't know any of the high-level details but here on the ground it's very real."
5:50pm - Newshub radio reporter Lauren Paddy is at the HQ of the White Island Tours. She says there are a number of people hugging and looking distressed.
Police are escorting them off around the corner.
5:38pm - Witness video shows a group of people desperate to get off the island during the explosion.
5:29pm - St John says it is in the middle of a "significant incident" on White Island.
"What I can tell you is that we have multiple casualties with significant injuries such as severe burns," director of clinical operations Norma Lane told Newshub.
5:21pm - Dramatic footage shows the moment White Island erupted.
5:08pm - Police say one person is critical and many still remain unaccounted for.
"While it was initially believed there were approximately 100 people on or near the island at the time of the eruption, we now believe there were fewer than 50," a spokesperson says.
"Some of those people have been transported to shore, however a number believed to be on the island are currently unaccounted for.
"Of those transported to shore, at least one has been critically injured."
Police are working with the National Emergency Management Agency to coordinate a search and rescue operation.
"Emergency services are working to ensure the safety of everyone involved, including rescue staff," the spokesperson says.
"A volcanic eruption is hazardous in the immediate vicinity of the volcano."
4:49pm - GeoNet says there remains "significant uncertainty" about the future but there are no current signs of escalation.
4:53pm - MetService has withdrawn its ash advisory. Airways NZ says no commercial flights have been affected.
4:47pm - St John officers from Whakatāne are travelling to White Island via the Coastguard.
Seven helicopters have been dispatched to the island with paramedics on board.
St John believes up to 20 people on the island require medical treatment.
4:42pm - Volcanic Air has confirmed it had a helicopter on Whakaari/White Island at the time it erupted this afternoon. Five people had flown to the island in the helicopter, but all are accounted for and have arrived back in Whakatane by boat.
The company has enacted its emergency response plan and says its priority was looking after the pilot and passengers.
3:38pm - The first victims are arriving back on the mainland.
4:25pm - It's being reported many of those on the island were from a cruise ship visiting New Zealand, Ovation of the Seas.
4:21pm - Simon Bridges has offered his thoughts to those affected by the eruption.
4:12pm - Speaking at Monday's post-Cabinet press conference, Prime Minister Jacinda Ardern said it's an evolving situation.
"We believe around 100 people were on or around the island at the time, and some of those are at this stage unaccounted for," she told reporters.
"A number of people are reportedly injured and are being transported to shore.
"Obviously it does appear to be a very significant issue, particularly the scale of those affected at this stage."
4:10pm - GNS volcanologist Brad Scott told Magic Talk's Ryan Bridge it was a significant eruption.
"It was quite an explosive eruption and significantly impacted the island and the main crater floor area.
"Unfortunately there's not a lot of shelter on the island - the people on the island were quite exposed.
"We have significant concern for people that may have been on the island."
4:07pm - It's believed the force of the eruption tipped a helicopter on the island over.
4:pm - MetService says the eruption was so large it was visible from space.
3:55pm - A group of people can be seen on a GNS camera walking close to the crater just minutes before the eruption.
3:45pm - WeatherWatch has released wind maps showing the current path of the ash.
3:42pm - St John says it's sending five helicopters to White Island. 20 people are believed to need medical assistance.
3:31pm - St Johns has confirmed to Newstalk ZB that they have reports of up to 20 injured in the eruption.
3:27pm - Police now have a cordon up at Whakatāne Heads and Muriwai Drive.
3:26pm - Ōpōtiki resident Maree Reeve told SunLive: "I certainly haven't seen a puff like this, possibly in the whole 18 years of living here".
"You can see stuff falling from the cloud."
3:24pm - Newshub has been told there were people on the island at the time. One boat from White Island Tours has returned, and a second boat is on way back - each boat holds up to 60 tourists.
Coastguard with paramedics are believed to be heading out to meet the second boat, in case of injuries.
Ambulances and police are waiting to meet the boat when it comes in.
3:18pm - The Ministry of Civil Defence warns it is hazardous in the immediate vicinity of the volcano, and ashfall might affect wider areas.
People living in or near the affected ashfall areas should:
- Be aware of the potential for ashfall. Consider staying indoors. Volcanic ash could be a health hazard, especially if you suffer from breathing difficulties
- When indoors, close all windows and doors to limit the entry of volcanic ash
- If caught in volcanic ashfalls: Wear a dust mask or use a cloth handkerchief over your nose and mouth; protect your eyes by wearing goggles. Wear eyeglasses, NOT contact lenses as fine ash will get under the lens
- Listen to the radio and/or TV for further assessment and updates
- Effects of a volcanic eruption can be experienced many kilometres from a volcano.
3:16pm - Police are warning the public to avoid the Whakatane Heads and Muriwai Drive areas. Muriwai Drive will be closed from Harvey Street.
3:15pm - Local 1XX reporter Alexander Goldsmith says a rescue operation is underway.
"We're getting numerous calls from the public," he says.
He said they have reports of people with burns injuries.
"We can't confirm anything so far about the extent of the injuries," he says.
"We do know it's very serious."
3:05pm - There are reports people were on the island at the time of the eruption and several are injured.
A local reporter says a rescue operation is underway.
3pm - MetService has issued a volcanic ash advisory for aircraft.
2:53pm - A local resident can see White Island from his deck and says it looks "spectacular".
"There's a lot more steam than normal, I don't know if it is a full eruption, but it looks pretty spectacular," Don Richards told Newshub.
2:15pm - An eruption is underway on White Island, near the Bay of Plenty. GNS confirmed to Newshub the eruption began at around 2.15pm on Monday.