UPDATED 10.21AM: A total of 900 people have now been evacuated from Kaikoura following Monday's earthquake and seemingly endless aftershocks.

MORE: Calls for 24/7 quake monitoring service

MORE: Damage growing in Wellington with each aftershock

The east coast town has been almost completely isolated since the 7.8 rumble hit just after midnight, with roads severely damaged.

Another 186 people have been ferried out this morning by the Navy ship Canterbury - most of them tourists.

They've been greeted with sunny conditions in Christchurch after an six-hour trip by sea.

Civil Defence is running an evacuation centre at the Arena - from where family and friends are collecting their loved ones - and tourists are being helped to find somewhere to stay.

Takahanga Marae in Kaikoura has taken in hundreds of people over the past week, but will serve its last meal tonight.

Civil Defence Controller John Mackie said he's thankful for the generous support the marae has offered.

People with ongoing needs will be redirected to Civil Defence and other support services.

The quake released the same amount of energy as 400 atomic bombs detonating, but the real fallout is already beginning to be felt by Kaikoura's businesses, which rely heavily on tourism.

Whale Watch, the town's biggest employer, caters to around 100,000 visitors every year, but is now at risk of deluge of cancellations.

"We were heading for an amazing summer season and had tens of thousands of advance bookings," Whale Watch owner Kauahi Ngapora said.

"Overnight, that has completely changed and there is huge uncertainty about where we go from there."

New Zealand Transport Agency has been working around the clock to fix bridges on a local, inland road previously known as State Highway 70 - into the town to provide limited access.

But repairing its State Highway 1 lifeline and the rail lines either side of the South Island township will take months and is likely to cost hundreds of millions of dollars, Transport Minister Simon Bridges says.

The quake also lifted the seabed more than a metre, rendering the marina used for launching the tourism boats, useless at present and this may need to be dredged or rebuilt elsewhere.