Independent senator Jacqui Lambie has spoken out on her secret deal to release refugees – describing it as the hardest decision of her political career.

The Tasmanian senator’s pivotal role in the deal, which involves Australia accepting New Zealand’s nine-year-old offer to take refugees, was revealed on Thursday.

The arrangement will initially be for refugees who are in Nauru or temporarily in Australia under regional processing arrangements and meet New Zealand’s refugee program requirements.

They must not be in other third country resettlement pathways, such as through Australia’s resettlement arrangement with the US.

It came more than two years after the Morrison government secured Senator Lambie’s pivotal vote to overturn controversial laws allowing for the medical evacuation of sick asylum seekers on Manus Island and Nauru.

Tweet from @JacquiLambie

Senator Lambie wept in late 2019 as she voted in favour of repealing the laws. Prime Minister Scott Morrison refused to reveal at the time if there was a “secret deal” to allow the refugees to eventually resettle in NZ.

He has repeatedly denied any plans to accept the offer – including while standing with NZ PM Jacinda Ardern in early 2019.

“When it comes to the New Zealand arrangement … the Australian government has no plans to take up that arrangement whatsoever,” he said.

On Thursday, Senator Lambie confirmed that a deal did exist – claiming that Mr Morrison had even told her she could go to jail if she revealed it. She said Mr Morrison was “intimidating” and “bullish” during the negotiations.

“I told him to show some humanity and get those people off those damn islands,” Senator Lambie said in a statement posted to her social media on Friday.

“I ended up negotiating an agreement with the government I couldn’t disclose.

“For years I held up my end of the agreement. Yesterday, the government held up their end.”

Earlier, she told the ABC that Mr Morrison’s warning felt like “more of a threat”.

“There was no need to do that because I already knew, quite clearly, if anything was said that deal would be off and all those people would be sitting on Nauru,” she said.

“I was in the room that day and I can tell you now what was said was intimidating.

“I spent 10 years in the Army. It takes a lot to intimidate me.

“It was intimidating, what was said. It was bullish and I’ll stand by that.”

Senator Lambie said she had tried to remain calm throughout the years since the medevac vote.

“I’ve tried to remember that any level of frustration, anxiety, disappointment or anger I was feeling about this taking forever, those asylum seekers were feeling at levels I couldn’t even comprehend,” she wrote.

“I was told if I disclosed the terms of the deal, there would be no more deal.

“I don’t believe that was said out of malice.”

Nonetheless, she said it “took longer than I wanted to” for the government to honour the agreement. That was partly because, ahead of its own election, New Zealand  was “nervous about who they’d be accepting”.

“They needed to do their own assessments. That took time. And, because of COVID and border closures, it took a lot of time,” Senator Lambie said.

She said she stood by her deal with the government.

“I agreed to repeal medevac in exchange for an end to offshore detention. An end which, when secured, would mean we wouldn’t have a need for medevac,” she wrote.

“I stand by it.”

“It won’t restart the boats. It won’t keep costing the taxpayer. It will put a line in the sand.

“I’m grateful we got there in the end. And I hope this means those asylum seekers can get back to living their lives. Finally there’s some light at the end of the tunnel.”

Senator Lambie said the decision to vote to repeal the medevac laws “was the hardest I’ve ever had to make in my political career”.

Scott Morrison with Jacinda Ardern in Auckland in early 2019.

Announcing the government’s acceptance of the offer on Thursday, Home Affairs Minister Karen Andrews reiterated that no one who travelled to Australia via boat would be resettled.

“Australia remains firm – illegal maritime arrivals will not settle here permanently,” she said.

“Anyone who attempts to breach our borders will be turned back or sent to Nauru.”

Labor welcomed the deal, but said it came much too late. Home affairs spokeswoman Kristina Keneally said the announcement was another pre-election promise to “protect inner-city Liberal seats” and questioned whether the Liberals would implement the deal.

Adrian Edwards, UNHCR regional representative for Australia, New Zealand and the Pacific, has also welcomed the announcement, saying the prolonged uncertainty refugees faced had taken an enormous toll.

But he said the 450 refugees it included would not be enough to cover the more than 110 asylum seekers on Nauru and some 1100 others in Australia.

Amnesty International Australia refugee adviser Graham Thom was disappointed that more than 100 asylum seekers in Papua New Guinea were excluded.

“Solutions will still need to be found for them,” Dr Thom said.

“We also can’t forget to acknowledge this important step that people have had years of their lives taken from them pointlessly.

“The government could have taken up this offer eight years ago and spared these people ongoing and arbitrary detention and the trauma of that experience.”

-with AAP