A navy ship was steaming towards the seaside town of Kaikoura, which bore the brunt of the quake that claimed two lives when it struck yesterday.
Huge landslides have cut road and rail links to the town, where police say water is running low, power is intermittent and hundreds of people are staying in evacuation shelters.
It has a population of 2,000, bolstered by an extra 600-1,000 tourists attracted by the area's popular whale-watching cruises.
Four military helicopters will begin ferrying them in small groups to Christchurch today and a C-103 Hercules is on standby to drop supplies to the stricken town.
Also Read
State broadcaster Radio New Zealand reported up to 50 civilian helicopters would also be drafted into the rescue effort, evacuating tourists from local rugby grounds.
The HMNZS Canterbury set off from Auckland yesterday and is expected to arrive in Kaikoura early Wednesday.
Commanding officer Simon Rooke said it could take up to 500 tourists.
"We're going to pick them up by landing craft and sea boats and extract them to Lyttelton (in Christchurch) so they can get to a point of safety," he said.
There have also been more than 800 aftershocks, some measuring more than 6.0, further complicating the work of emergency crews.
Prime Minister John Key said he was shocked at the scale of the damage after flying over the quake's epicentre on yesterday.
"It's just utter devastation... Months of (repair) work," Key remarked, adding that repairs would likely take "billions of dollars to resolve".
The tremor, one of the most powerful ever recorded in the quake-prone South Pacific nation, hit yesterday.
Disclaimer: No Business Standard Journalist was involved in creation of this content