'Tough calls' to be made on future of climate-vulnerable communities - Chris Hipkins

Prime Minister Chris Hipkins says Aotearoa has "some tough calls to make as a country" regarding the future of communities in places vulnerable to extreme weather events.

His comments follow record-breaking rainfall last weekend over Auckland, which caused widespread flooding, four deaths and is predicted to cost insurers close to $1 billion, if not more.

"In terms of a weather-related natural disaster, it's probably the biggest one we've ever faced as a country," Hipkins told RNZ's Nine to Noon on Thursday.

"We do have to be prepared for the fact that this isn't going to be solved in the next few days or weeks. It is going to take quite a lot of time," he said, when asked about the scale of the disaster and repair job ahead.

"Some of those houses will need significant work on them, some of the buildings will need significant work on them. And of course, the infrastructural challenges that we knew Auckland had, have been well and truly brought to the fore I think in what we've seen in the amount of time it's taken to clear some of the water, and so on."

Green MP Chlöe Swarbrick earlier told the New Zealand Herald a map of Auckland floodplains, freely available on the council's website, was a "clear match" for the regions most affected by the flooding over the weekend.

Auckland Mayor Wayne Brown on Saturday morning, as the city's residents woke to reports of major flooding, said at a media conference "some of those houses, when you think about it, actually shouldn't have been where they are".

Hipkins said after the emergency response is wrapped up, that will need to be looked at.

"Look, we've got some tough calls to make as a country - including looking at things like where have we built houses, are there particular communities that are going to be more vulnerable, do we need to do more in those areas?

"Some people have already started to get into that conversation around Auckland now - I think, let's just get the water out of the way first, then there will be an opportunity to have those conversations.

"But they're things that we're going to have to work through as a country - we are likely to see more of these extreme weather events, so we're gonna need to make sure we respond to them, and respond quickly and better."

He said whatever decisions the government and councils do make, they need to "have a degree of unanimity, or near-unanimity" with support from across the political divide.

"These are complex problems and the answers to them are not easy, when you're talking about potentially whole communities that might be in a vulnerable area that's difficult to remediate.

"That involves some tough conversations and is potentially a very expensive challenge to deal with as well. These aren't going to be issues that we solve overnight, but we've got to make the space to do that."

As for how much financial contribution central government could make to Auckland's immediate recovery, Hipkins said it was "a bit too early" to say, "but we know it's likely to be significant".

"Once we've got a sense of exactly what remediation work is gonna be required, then we can sit down with Auckland Council - and we absolutely will - and figure out how we can do that fairly and equitably."

The Greens have prepared a climate adaptation bill to cover managed retreat from vulnerable areas, with private insurance companies signalling some properties might soon become uninsurable due to the growing risk. National has indicated it is willing to work with the Greens to create a policy that will survive successive governments.

Hipkins said the bill is yet to come before the House, and he has not given it a close look since becoming prime minister, with his focus so far being on the immediate emergency in Auckland. He doubts it will be Parliament's final word on adapting to a warming planet.

"We know this is a challenge that's not going to go away, so we're going to have to do it right. And almost certainly, we'll need to continue to evolve and adapt. One bill through the House isn't going to deal with every issue. We'll almost certainly need to be revisiting it time and again."