The Coalition has secured crucial crossbench senator Jacqui Lambie's support to repeal refugee medical evacuation laws.
Senator Lambie, a Tasmanian independent, has backed the federal government's move to bring the medevac repeal bill to a vote on Wednesday morning.
Government Senate leader Mathias Cormann has said it was in the national interest for politicians to leave Canberra after the final sitting week with a stronger border protection regime in place.
He said repealing the laws was a core promise the Coalition took to the election earlier in the year.
"Today the Senate will have an opportunity to side with the government in support of stronger national security and against weaker national security arrangements," Senator Cormann said.
Labor home affairs spokeswoman Kristina Keneally said the government had clinched a deal with Tasmanian independent Jacqui Lambie, who holds the deciding vote.
"The Parliament and the Australian people have a right to know what this secret deal is," she said.
"A deal between the Morrison government and Senator Lambie to drive a stake through the heart of medevac and they're keeping it secret from this parliament and from the Australian public."
Greens leader Richard Di Natale said the laws provided refugees and asylum seekers in offshore processing with basic human rights.
"We've got a government working with Senator Lambie to repeal laws that provide people access to health care," he said.
"That's all that medevac does."
It's understood the government may have agreed to send refugees from offshore processing to New Zealand after a similar arrangement with the US has ended.