A significant proportion of Pacific Islanders affected by climate change would be accepted into New Zealand under policies drawn up by the Labour and Green parties.
The Green Party says the relocation of people affected by global warming needs to start immediately, but the Immigration Minister is accusing both parties of using the issue in a bid to grab votes among the Pacific community.
Climate change 'refugees' have started knocking on New Zealand's door, but National says the case for opening that door hasn't yet been made.
Immigration Minister Michael Woodhouse said New Zealand should continue to focus on the many refugees waiting in camps for resettlement for decades and leave the issue of climate change to the United Nations.
"That could be years or even generations away and I think it's speculative, and as I say quite patronising, for Labour and the Greens to say 'we are the solution' in order to gain votes from the Pacific community."
Mr Woodhouse said New Zealand already accepted 1500 people a year under the Pacific Access Category and the Samoan Quota.
An i-Kiribati man is appealing to Mr Woodhouse after he failed in his legal battle to stay in the country as a climate change refugee, saying that rising sea levels were making his homeland uninhabitable.
But a Tuvalan family this year became the first to be granted residence on humanitarian grounds that included the effects of global warming on conditions in their home island.
Green Party spokesperson on global affairs Kennedy Graham said people need to be relocated now.
"We can either wait until it's too late, and then you have en masse migration - somewhat chaotic - or you can do it on an advanced, planned basis. We're in favour of that."
Mr Graham said a regional climate relocation plan could be developed under the Pacific Islands forum or New Zealand could make bilateral agreements with Tuvalu and Kiribas, and potentially the Marshall Islands.
He said they would be climate change immigrants rather than refugees, because international conventions do not yet recognise people fleeing the effects of global warming.
Labour's immigration spokesman Trevor Mallard said the party planned to talk to the United Nations to see if it would change its refugee criteria, or, if not, New Zealand could go it alone.
He said the party's policy was to progressively increase the annual refugee quota from 750 to 1000 but did not yet know whether any climate change refugees would be in addition or included in that number.
And, unlike the Green Party, he believed there was still time for planning before anybody needed to be relocated.
"My view is that the number will be in the hundreds at some point, but will also be over a period of years. It won't be like it's all got to happen in one year."
Mr Mallard said it was important that New Zealand offered leadership on the policy, but that did not mean it should be the only country accepting people displaced by climate change.
UN Secretary General Ban Ki-Moon, who was at the Small Island Developing States conference this week, said affected islands need the full support of developed nations to fight climate change.
But he said the issue of climate change refugees can only be addressed when there is the political will among OECD countries to do so.