"They would have to think about their relationship with Australia," warned Australian Immigration Minister Peter Dutton.

Australian Immigration Minister Peter Dutton has opened the door to a potential refugee resettlement deal between New Zealand and Papua New Guinea, acknowledging it is a decision for the two sovereign states that Australia could not block.

But he warned any arrangement would be against Australia's wishes and would run the risk of souring both countries' diplomatic relationships with Australia – making it unlikely without Canberra's blessing.

"That's an issue between those two countries. Any sovereign state can enter into bilateral arrangements," Dutton said in a Sky News Australia interview on Thursday.

DANIEL MUNOZ/FAIRFAX AUSTRALIA Jacinda Ardern with Australian Prime Minister Malcolm Turnbull earlier this month, when she reiterated her offer to take 150 refugees from Manus Island.

"They would have to think about other equities within the respective relationships – they would have to think about their relationship with Australia."

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New Zealand has offered to resettle 150 refugees from Manus Island, where about 370 men are still refusing to leave Australia's decommissioned regional processing centre.

The men have remained on the site without food, water or power supplies since October 31, instead collecting rainwater in buckets and bins.

They say they will not move "from one prison to another" and fear for their safety at alternative accommodation in the Manusian town of Lorengau.

The unfolding humanitarian crisis has attracted widespread condemnation from the United Nations, major international charities and human rights observers.

Prime Minister Jacinda Ardern repeatedly reiterated New Zealand's resettlement offer to Australian Prime Minister Malcolm Turnbull, including at a recent summit of Asia-Pacific nations, but it has been politely declined.

To date, neither New Zealand nor PNG have been willing to circumvent Canberra, despite mounting concern in both countries about the refugees on Manus Island.

But Ardern has been urged by the Greens and the New Zealand Refugee Council to start talking directly with Port Moresby.

Australian Labor has urged the Turnbull government to accept the Kiwi offer, with immigration spokesman Shayne Neumann citing the one-off resettlement deal with the US as a precedent.

Dutton's remarks on Thursday indicate Australia has no lawful way of stopping New Zealand and PNG striking a bilateral deal. But he would frown on such an arrangement because it could lead boats to restart.

"The people smugglers are watching eagerly at the moment," he said. If there was a pathway to go from PNG to NZ to Australia, "the train reopens, and I'm not going to allow that to happen".

Dutton said he was not threatening the Kiwis or PNG, but "any sovereign nation, in any arrangement, would have to think about other equities in the relationship".

He pointed out that Operation Sovereign Borders, paid for and executed by Australia, also benefited New Zealand by intercepting and turning around boats bound for that country.

It is understood four boats marketed to asylum seekers as being bound for New Zealand - carrying 164 people - have been picked up and turned around under Operation Sovereign Borders.

"If any boats arrive tomorrow, those people aren't going to Auckland, they're going to the processing centre on Nauru," Dutton said on Sky News.

He also dismissed Ardern's undertaking to give $3 million for services for refugees on Manus Island and Nauru as "a waste of money".

Dutton again called on the 370 remaining men to end the stand-off and move into the alternative accommodation on offer.

"This is like the tenants who refuse to leave the house," he said. "They need to move out of the regional processing centre because it's not safe. They have trashed the place."

PNG police again declined to use force to remove the men as the stand-off entered its 17th day, despite earlier threats they would be forcibly moved to Lorengau.

One of the leaders of the resisting refugees, Iranian journalist Behrouz Boochani, said conditions at the site were deteriorating, including dirty toilets, polluted water and untreated infections.

"The bodies (are) getting weak and it's a real danger," he said. "We are living in a condition that is threatening our health."