Jacinda Ardern, Winston Peters clash over migrants using NZ to access Australia

Foreign Minister Winston Peters and Prime Minister Jacinda Ardern are at odds again - this time over whether New Zealand should stop migrants using New Zealand as a gateway to Australian residency.

Speaking from Nauru, where's he's attending the Pacific Islands Forum, Mr Peters said he's been warning New Zealand would be used as a backdoor to Australia since the 1990s.

He said New Zealanders lost "fundamental rights" in Australia because of migrants using New Zealand as a "bolthole" to eventually settle there.

"We can fix that up," he said. "The mechanism is to not give people the right if they have obtained a new status."

Prime Minister Jacinda Ardern said there will be no legislative changes, and she said she "wouldn't read" Mr Peters' comments as a suggestion of a law change.

"That's a decision for Australia," she said. "The focus for us is, of course, the offer we have made around providing assistance for 150 places for those deemed to be refugees".

It's the second time the coalition partners have been at odds over migration. On Monday, Mr Peters said he did not support the Government's plan to double the refugee quota to 1500 refugees a year.

"We never made a commitment to double the refugee quota," Mr Peters said.

That's despite comments from Immigration Minister Iain Lees-Galloway repeating Labour's campaign promise in July.

New Zealand has been offering to resettle refugees currently held in offshore detention centres for the past five years. The Australian government has expressed concern that refugees held in offshore detention could make their way back to Australia if they were first resettled in New Zealand.

In 2001, Australia cut New Zealanders' access to welfare payments and made the pathway to Australian citizenship more difficult. New Zealanders were singled out "because of the high proportion of New Zealand citizen migrants born in countries other than New Zealand," a 2017 Statistics New Zealand report says.

In the year ending April 2017, about one in four New Zealand citizens migrating to Australia were born overseas - but the numbers appear to simply reflect the number of New Zealanders born overseas rather than any "backdoor" route.

About one in four New Zealanders were born overseas in 2014, and they tend to move to other countries at about the same rate as other New Zealanders.