"In terms of getting a better assessment of what happens next, we have military helicopters that are available to us," Key said.
"[One] is going to be going down to Kaikoura very rapidly. The area is cut off from a road perspective...we want to put one of those helicopters down there, another one will be in Wellington.
"One of the purposes of bringing a helicopter down there, other than trying to provide reassurance to people, is also to make sure we can provide better [communications]."
Key said on the best information at the moment, the Government expected the number of confirmed fatalities would not increase.
The Prime Minister and Bronagh Key stayed at Premier House in Wellington last night. It was the biggest earthquake he had experienced in Wellington, he said.
"People will be feeling quite vulnerable...it was a very significant shock. It started a little bit more slowly, then it started building in its intensity. And people will appreciate, Premier House was built a long time ago so it is a structure that really rattles around.
"We had some glasses that were broken, and stuff in the room moving around quite a lot...and I just know from the Christchurch earthquakes, how much it undermines people's confidence."
Key said Cabinet would hold its usual Monday meeting today, and it was his expectation that he and Brownlee would then visit Kaikoura and other quake-affected areas.
Key was due to leave the country tomorrow to visit Argentina before an Apec meeting in Lima, Peru.
"We will take a call on that at some point. There's got to be a pretty reasonable chance that we don't undertake the Argentinian leg."
Key said New Zealand was in "great shape" to meet any costs from the quakes, but expected there would be significant repairs needed.
