Australia on Wednesday removed the right of doctors to order sick asylum seekers to be evacuated from two remote Pacific detention centers for medical treatment.
"We've always understood that that type of loophole doesn't strengthen our borders, it only weakens them", Mr Morrison said.
Lambie had indicated previously that her vote for the repeal would be conditional on the government meeting a condition which she would not specify.
"I don't like holding things back like this but when I say I can't discuss it publicly due to national security concerns, I am being 100 percent honest to you", she said.
Independent senator Jacqui Lambie has delivered the Morrison government a major win after voting to scrap laws making it easier for refugees to get medical transfers to Australia.
"I'm not anxious about the politics of this issue, I'm anxious about the people, the patients here at the centre of this system".
But Home Affairs Minister Peter Dutton said "people were already receiving" appropriate medical treatment before the Labor-backed medevac regime.
It is believed the government may have secured her vote by offering to send refugees from Nauru to New Zealand, after a similar resettlement deal with the United States is completed.
He said Cormann had "walked over to senator Lambie and said, 'Is it OK if I say there's no deal?' We heard you say it".
In opposing the repeal, opposition MPs said the government was "devoid of a heart".
With details of Lambie's secret deal with the Government yet to be announced, many Christians continue to pray today that her dealing has secured some benefit for those people who came to Australia seeking refuge and, instead, faced indefinite detention on Manus and Nauru. "My hand is on my heart and I can stand here and say that I would be putting at risk Australia's national security and national interest if I said anything else about this".
Polls show that 62% of voters support the law. The administration of US President Donald Trump said it would only honour that deal to maintain a strong relationship with Australia, and then only on condition that refugees satisfied strict checks.
The Medevac Bill, which passed despite the Morrison Government's best efforts to kill it dead at the time.
'There is no secret deal.
Australia's hardline immigration policy mandates that any asylum seeker arriving by boat will be processed offshore.
In October, Head of Operation Sovereign Borders, Craig Furini, told Senate estimates that 135 asylum seekers had been transferred to Australia for treatment, but only 13 were hospitalised upon arrival.
However, attention should swing to those still left on PNG, Nick McKim said "it's the darkest day for those people who remain on Manus and Nauru".
The Morrison government argues existing medical transfer provisions were adequate before the medevac laws were put in place and will not result in poorer treatment outcomes.