Battered by thunderstorms and aftershocks, visitors and residents will be given the option to fly out of the region on Tuesday - if the weather permits.

The township remains unreachable by road, due to massive slips and damage on State Highway 1 after a magnitude 7.5 quake hit just after midnight on Monday morning.

Helicopter crews from across the South Island are working overtime, with extra flights being put on by many companies.

The navy is also en route to the tourist hotspot, which is currently only accessible by sea and air.

"We are looking at four flights [Tuesday] morning and a total of 16 flights today. I must reiterate that's all weather dependent as is HMNZ Canterbury," New Zealand Defence Force (NZDF) Senior Lieutenant Commander Geoff Andrew said.

MetService forecasted spots of rain early Tuesday, but expected the rest of the day to be fine, with a high of 27 degrees Celsius.

A severe weather warning had been issued for Marlborough earlier, but the forecast severe gales were expected to ease mid-morning.

A heavy rain warning for the Richmond and Bryant Ranges had already been lifted.

Andrew said it was hoped 12 evacuees could be flown out of Kaikoura on each flight, with their luggage, to Christchurch. 

"From Christchurch they need to find their own means of travel around New Zealand."

Those with illnesses, pregnant women and people with children would be given priority. 

The navy vessel HMNZS Canterbury could carry 242 people and would "take as many as she can", Andrew said.

The vessel is expected to arrive in Kaikoura on Wednesday.

Many Chinese tourists are sitting on top of a hill, surrounded by luggage, in an area called Seaview waiting to fly to Christchurch.

William Luk, 25, from Hong Kong, said he was relieved to be leaving and felt "lucky to be alive".

The lack of cellphone reception and accessibility to the area made him feel "claustrophobic".

Luk said he was staying at a motel near the waterfront when the earthquake hit. He'd never felt one before.

"The sound was so loud. [Initially] we thought someone was trying to rob us ... banging on the door. Then everything shook."

Luk said when the shaking stopped he and a friend fled to higher ground because of the tsunami threat.

They spent the night under the stars. On Monday night they tried to stay at the emergency shelter, but it was full.

Luckily the motel took the pair in again and gave them a bed for the night, he said.

"People here are so helpful, so generous. It kind of restores your faith in humanity."

Luk said he was flying to Christchurch soon and would reassess his travel plans.

"I don't want to say [my holiday is] ruined, but I don't know what's going to happen in the next few weeks."

English tourists Janice and David said they had received mixed messages about what they were meant to do following the quake.

"It's been a horrific experience, we were both frightened for our lives," Janice said.

"It's been frustrating, we've had conflicting messages about what we are to do."

David said they hoped to leave Kaikoura on Tuesday. 

Andrew said the volunteers working in the area were "doing the best job they can" to help those in need.

"They're doing a fantastic job. Disorganisation comes with any event of this scale," he said.

Hundreds of aftershocks have kept residents of North Canterbury on edge.

"It wouldn't have been the most comfortable night," Hurunui District Council chief executive Hamish Dobbie said on Tuesday morning.

Civil Defence's acting national controller Shane Bayley said anyone who wanted to get out would be able to do so on helicopter flights throughout Tuesday.

There were four NH90 helicopters in operation "ferrying people in and out as well as supplies", which would be used to fly out those wishing to leave.

Tourists began being airlifted out of the region on Monday night, with a chartered helicopter flying some Chinese nationals out, Bayley told media in a briefing at Civil Defence's national emergency control centre at Parliament.

Tour agency Stray Travel planned to fly a private plane in on Tuesday morning to carry 30 foreign tourists and their driver to Christchurch.

It was not yet known if heavy rain and strong winds would hamper flights out on Tuesday.

"The weather's always going to be a factor, and potentially it will affect helicopter flights and the use of ships," Bayley said.

However, the weather was forecast to ease later on Tuesday.

Two Navy vessels en route to the area from Auckland would arrive on Wednesday morning with supplies, and would also evacuate people.

The full extent of the damage to the area was still not known.

On Monday night, between 70 and 100 people remained at Takahanga Marae with nowhere to go.

That was a significant drop on the 700 people who had stayed at the marae following the earthquake in the early hours of Monday morning.

The Canterbury Civil Defence Management Group would send building inspectors and council staff into Kaikoura on Tuesday to "support the response and to boost capability on the ground".

"There's a lot of activity planned for today," Bayley said.

Power and communications were still "intermittent" and there was a big effort going on to get the inland roads into Kaikoura up and running but it will take a couple of days.

As for reopening State Highway 1, which was closed between Blenheim and Kaikoura, and Seddon and Chevior, Bayley said, "that's a major project".

In the meantime, those still in Kaikoura were asked to sit tight.

They were urged to conserve water, with just three days' supply remaining.

"The message is to conserve water and be prepared for a long period of time not being supplied properly," Bayley said.

A welfare centre remained open in Waiau, one of the town's hardest hard by Monday quake. Other welfare centres in the district closed after the tsunami warning was lifted. 

Leader Rd and Inland Rd, between Waiau and State Highway 1 on the east coast, remained closed on Tuesday. 

State Highway 7 (Lewis Pass) reopened on Monday, and one lane of State Highway 7A to Hanmer Springs village reopened on Tuesday morning. 

"We understand some people have got through (on Leader Rd) but we understand it's pretty difficult going through there," Dobbie said.

Some local roads were also expected to have been damaged. 

"There's a lot of roads that we haven't got to through there, so we don't know what the condition of them is yet."

The council's priority on Tuesday was getting Inland Rd open between Waiau and Kaikoura and restoring power back to water pumps across the district, Dobbie said.

Generators were being used to keep affected pumps going, but residents were urged to conserve water until power was restored and should boil water as a precautionary measure until further notice. 

"We're asking people to only use what they need."

Stuff