It follows accusations from the head of the United Nation's refugee agency that Australia misled the UN while seeking its support for the deal.
In a forthright statement, the head of the United Nation's refugee agency, Filippo Grandi, has accused the Australian government of backtracking on an agreement to resettle some people in offshore detention in Australia.
The statement from the UNHCR details how the agency agreed to help with the relocation of refugees on Manus Island and Nauru to the United States, in a deal struck in November.
But it said its support was based on the clear understanding that vulnerable refugees with close family ties in Australia would ultimately be able to settle there, something the Turnbull government is refusing to allow.
Canberra-based external relations officer for the UNHCR, Catherine Stubberfield, explains.
"The UNHCR's involvement within the Australia-US relocation of refugees was also based on the fact that those refugees with close family in Australia would be allowed to settle here. Australia's refusal now to take those refugees is contrary both to the principles of family unity and to refugee protection."
Ms Stubberfield says the UNHCR has been working with less than 50 individuals they view as eligible for consideration to be settled in Australia due to family ties.
She outlined one case involving five brothers.
"A group of five young men arrived during 2013, all together - they're brothers. Of that group, 2 of them were sent to Christmas Island and then later transferred to Australia. Another three went together to Nauru and two were later evacuated for medical reasons. What we have now is the youngest brother who was a child when he arrived, 17 years old and he's stuck on his own. All his brothers live in Perth, and he's speaking with us saying that I'd really like to be with my family, they've all been through a lot, I've been through a lot and it's perfectly reasonable in that circumstance that families be reunited here."
Foreign Minister Julie Bishop says the government has been clear about its position from the outset, and that no refugees housed on Manus or Nauru will ever be settled in Australia.
"My understanding is that the Australian government's position has been clear and consistent throughout and I've not heard any change to those arrangements. If people seek to arrive illegally, if they pay criminal people smuggling networks and they're transferred to a regional processing centre, they will not be resettled in Australia."
The UNHCR has raised concerns about people with serious medical conditions, or who have experienced trauma while living offshore, who will now be unable to access support from family in Australia.
Refugee coordinator at Amnesty International, Dr Graham Thom says it's not surprising the UNHCR took the unusual step of criticising the Australian government.
"For them to be so forthright in claiming that Australia has reneged on a promise to re-settle at least the families and not separate families is quite extraordinary and is certainly welcome. We can only hope that the Australian government will in fact live up to its agreement and makes sure those families are not separated."
Those sentiments have been echoed by Human Rights Watch, the Refugee Council of Australia and the Asylum Seeker Resource Centre, all calling on the Turnbull government to reunite those families who have been split up.
The UNHCR says it is urging a reconsideration of the government's position and is hopeful that will still occur.
