Refugees in offshore detention could be sent to New Zealand under a compromised deal to scrap controversial medevac laws.

Senate crossbencher Jacqui Lambie has offered to help the Morrison government unwind the laws, on one condition.

Senator Lambie has refused to publicly state what that condition is, citing national security concerns.

“Only three offices know the condition – mine, the PM’s and the minister. Everyone else is just speculating,” she tweeted on Thursday.

But sources close to the negotiations told Nine newspapers her vote could be secured in return for accepting the New Zealand deal.

New Zealand has long offered to take 150 refugees a year from Australia’s offshore processing centres in Papua New Guinea and Nauru.

The Coalition and previous Labor governments have refused to accept the offer, claiming it could trigger an influx of asylum-seeker boats.

I’ve had 10 journo’s put to me unsourced rumours about what I’ve proposed to the Govt – but I can’t comment on any. Only 3 offices know the condition – mine, the PM’s & the Minister. Everyone else is just speculating. #auspol

— Jacqui Lambie (@JacquiLambie) November 27, 2019

Refugee Behrouz Boochani, who spent more than six years in detention in Papua New Guinea, urged the government to seize the deal.

“Right now the government doesn’t have any [other] way. They should accept New Zealand’s offer,” he said.

“If they accept New Zealand’s offer we can say that it’s almost finished. It is a big chance for the government, a big opportunity.”

Home Affairs Minister Peter Dutton is tight-lipped on the ultimatum.

“Obviously we’ve been in discussions with Jacqui and it’s just not something I can comment on publicly at the moment,” Mr Dutton told 2GB radio.

He needs Senator Lambie’s vote to repeal the medevac laws.

“I think Jacqui can support the bill and she should support the bill, because it’s very clear that we’ve brought people to our country who are of bad character,” Mr Dutton said.

“There are six people who are here that we worried about and 10 on the way that we have, under the law, no ability to stop.

“They are people of poor character that we don’t want in our country.”

The medevac laws, which passed against the government’s will earlier this year, gave doctors a greater say in granting medical transfers to sick refugees being held offshore.

There have been 179 people brought to the Australian mainland for treatment under the medevac laws.

Almost 500 refugees and asylum seekers remain on Nauru and in Papua New Guinea.

The Senate is expected to debate the medevac laws next week, before parliament breaks over summer.

-AAP