New Zealand is still willing to take asylum seekers from Australia's offshore detention centres but Scott Morrison says it's even less likely to happen than it was before.
The offer has been standing since 2013, but successive Australian Labor and Liberal prime ministers have rejected it.
Reports on Friday said New Zealand officials had privately told former prime minister Malcolm Turnbull they weren't open to resettling single men from Manus Island and Nauru.
But NZ Prime Minister Jacinda Ardern wanted to "correct the record" to let Australia know the offer still stands, dependent on security advice.
"We have been utterly consistent. UNHCR themselves, in the way that they work through with refugees, does place some priority on women and children," she told reporters in Auckland on Friday.
"It was never, however, the case that our offer across Manus and Nauru was solely around women and children, but of course we acknowledge the special need that existed there."
Ms Ardern said if Australia was to take up the offer, New Zealand would do its own security checks on the asylum seekers.
Mr Morrison confirmed there are only single males left on Manus Island, with a number failing character tests.
"If you would apply the normal character test that applies to all other persons who would seek to come to Australia, whether they are a student, a visitor or anything else, you wouldn't allow them in," he told reporters.
"That is why we are concerned about what passed the parliament last week, because it compromises our ability to prevent the transfer."
Almost 60 asylum seekers on the islands have failed character assessments since the Department of Foreign Affairs and Trade began screenings in response to new medical transfer laws, according to The Australian.
The Morrison government has attacked the new medevac regime, arguing there's a loophole that prevents people being sent back to Manus Island and Nauru once they have been transferred to Australia for treatment.
"That, I think, now makes (the New Zealand offer) even more difficult than it was before, and we weren't taking it up before," Mr Morrison said.
But Labor rejects the claims and vows to return asylum seekers once doctors advise they have completed medical treatment.
Labor leader Bill Shorten said the government believed inaction was a better solution than accepting New Zealand's offer.
"I'm concerned that the current government sat on its hands for four years when New Zealand made an offer," he told reporters in Canberra.
Labor prime ministers Kevin Rudd and Julia Gillard also declined the offer.
The government intends to send people to the reopened Christmas Island detention centre, off Western Australia, rather than the mainland.
Australian Associated Press