Canterbury earthquakes: Aftershocks sweep through

Canterbury earthquakes: Aftershocks sweep through

Earthquakes have rocked the upper South Island overnight, with nearly 200 aftershocks felt in the last 12 hours.

A magnitude-5.7 aftershock at 6:30pm on Tuesday caused chimneys to collapse and sent people out onto the streets of Waikari, north of Canterbury.

Hurunui District Council says it knows of at least five houses that have been badly damaged by the aftershock.

The tremors prompted Canterbury Civil Defence to close the Kaikoura Inland Road after the Tuesday afternoon aftershock.

However the Inland Road but was reassessed early on Wednesday morning and is now open to a New Zealand Defence Force (NZDF) convoy carrying essential supplies to the community. 

The road is an important emergency access route that allowed farmers, NZDF and essential services to make their way to the coastal town on Tuesday.

"Any delay is a cause of great frustration for all of us but people's safety is our top priority when it comes to the use of this route," Civil Defence duty controller Brett Aldridge said.

"The movement orders for the day will be reworked so if and when it is safe to proceed, we can get things moving again as quickly as possible."

An NZDF convoy scheduled to take supplies to Kaikoura however escorted access to Mt Lyford is still on hold.

Cantabrians are being urged to steer well clear of the Conway River because of the threat posed by an earthquake-generated dam.

Mr Aldridge says last night's intense aftershock in Waikari could have made things worse.

"We're getting people up there at first light just to see the state of that dam - obviously after last night's quake, things could have changed," he said.

Mr Aldridge says an overflow could cause a rapid water level rise change and debris downstream on the river.

Meanwhile the New Zealand Transport Agency is still unsure when it will be able to begin the mammoth task of cleaning up State Highway 1 along the Kaikoura coast.

Spokesman Mark Owen says many communities still don't have road access.

"The first priority is getting access to people that are isolated, then we can start the bigger task of dealing with those pretty significant slips that are in there," he said.

North Canterbury resident Dave Blackler took Newshub through his home on Wednesday morning to show the damage his home sustained in last night's aftershock.

"We'd cleaned up after the last one," he explained, as he looked around at the overturned bookshelves, smashed glass and fallen items strewn across the floor.

Canterbury earthquakes: Aftershocks sweep through

Mr Blackler was optimistic in the face of the utter turmoil that surrounded him.

"Crack-wise it's not too bad, to be honest - it's hung in there," he said, crediting his home's Ministry of Works design for the lack of structural damage.

However, Mr Blackler said last night's aftershock had affected his home and caused more damage worse than the destructive Canterbury earthquake of 2011 had.

"Last time there were just a couple of cracks and the tiles lifted - but now they've popped off and this sort of mess has left us back at square one. There's a bit more [that's fallen] out of the cupboards."

Canterbury earthquakes: Aftershocks sweep through

Mr Blackler said while he's upset, he'll battle on, as there's not a lot he can do about it.

"It's just one of those things. We were fortunate in a way that we didn't go through what they did in town [during the 2011 quake], and we didn't get them out here.

"It's our turn now - we can sympathise more with what they've gone through in Christchurch over a long period."

Since Tuesday evening, shakes have been felt from Auckland all the way to Invercargill.

Kaikoura, Culverden and Seddon have experienced the tremors more frequently than other communities. Cheviot felt the biggest shake, with a magnitude-4.7 quake striking just before 11pm on Tuesday.