A further 34 men have been told they will be freed from detention facilities in Melbourne on Thursday, the Asylum Seeker Resource Centre claims, following the release of about two dozen detainees on Wednesday.
But 14 men will remain in a makeshift detention centre in a Melbourne hotel, with no obvious reason for the different treatment.
Home Affairs Minister Peter Dutton told 2GB on Thursday the releases were about saving money and that the released men had been assessed as not being a threat.
"It's cheaper for people to be in the community than it is to be at a hotel or for us to be paying for them to be in detention," Mr Dutton said.
He added that it was difficult to return people offshore and that some of the detainees had lodged legal action in Australia.
One of the men slated for release on Thursday is Mardin Arvin, an Iranian refugee who spent six years in Papua New Guinea after seeking asylum in Australia by boat.
He has been held in Melbourne hotels since he came to Australia for treatment under the now-repealed 'medevac' law in November 2019.
Mr Arvin, 32, told AAP he was looking forward to spending some time alone without being surrounded by security guards.
"I wish to be alone and working...and get some fresh air, sunshine," he said.
Mr Arvin wrote on Facebook that he could not be completely happy until all Manus and Nauru refugees were free.
One of the 14 who will remain in detention told AAP that he was "very upset".
"I became very weak and I'm really broken down because of this situation," he said.
The refugee has not been given a reason for his ongoing detention and said there was no obvious difference between the 14 and those who will be released.
"This my question," he said. "I want to know exact reason what I did and what is my wrong."
A Home Affairs spokesperson told AAP they do not comment on individual cases.
The Melbourne hotel and another in Brisbane were designated as alternative places of detention by the federal government, and have been the centre of fierce protests during the past year.
The men held in them were brought to Australia for medical treatment under the short-lived 'medevac' legislation.
Repealed in December 2019, the law allowed independent doctors to recommend the transfer of people held in Nauru and Papua New Guinea to Australia for medical purposes.
Sri Lankan refugee Ramsiyar Sabanayagam, 29, will also be released from the Park Hotel on Thursday.
He was just 22 when he arrived on Christmas Island and was sent to Manus Island.
The hotel he was held in for over a year before being transferred to the Park in December was like a prison, with no sunshine or fresh air, he said.
He is looking forward to hugging and thanking his supporters.
"First of all I want to meet my friends...because lots of supporters, brothers and sisters and grandmothers, day by night they are supporting us and fighting for us," he told AAP.
While happy to be released, Mr Sabanayagam said that a six-month bridging visa was not enough and that he had been waiting for a permanent solution for too long.
The Department of Home Affairs told AAP in a statement: "The Australian Government's policy is clear that no one who attempts illegal maritime travel to Australia will be permanently settled here."