Refugees occupying the decommissioned detention centre on Manus Island have been given two days to leave by the Papua New Guinea government, or face forcible eviction.
In a letter to about 600 men, the government said it had great concern for their health after a week in the centre without basic services and sanitation utilities.
It said if necessary force would be used to relocate those who refused to leave voluntarily to three facilties in the island's main town, where services were available and security was guaranteed.
The letter said the demolition of the centre's fences would begin today and those remaining would be deemed to be unlawfully on a military base and face eviction or arrest.
In response, Kurdish journalist and refugee Behrouz Boochina said the use of force would be completely unacceptable, as the men were "resisting peacefully".
He said they wanted to be resettled in a "safe third country" and not other prisons on the island.
Just back from Manus Island, Amnesty International's Kate Schuetze said the alternate facilities were not ready.
"They're not able to cope with the numbers of people they are not yet secure and fully built sites," she said.
"The East Lorengau Transit centre has been open for some time but that was built to accomodate 300 people, we have nearly 700 people on Manus in total right now."
But Manus province's Governor, Charlie Benjamin, said the facilities in Lorengau were ready.
"Most of them will be going to East Lorengau, that already has facilities there. And some of them will be on the new location," he said.
"But I can assure you that, maybe one or two things, but facilities are more than ready to accomodate them. I don't see that as a problem. I think it is an issue made by asylum seekers just to get the international community to be more sympathetic to them, when I think they have been taken care of very well."
However, advocate Ian Rintoul from the Refugee Action Coalition said two of the three alternate facilities did not have perimeter fences.
He said removing the fences from the detention centre showed "the contempt that the Australian and the PNG governments have for the security of refugees who are in their care and need protection."
"It also shows the contempt for the governments' responsibility to provide permanent security for the refugees and asylum seekers. Their demand is for enduring protection in a safe, third country."
Ms Schuetze said there were simple solutions to address the PNG government's concern for the health of refugees, a situation she said was of its own making by disconnecting services from the centre.
"This crisis that they've created is because they've actively blocked medical professionals going to that site food deliveries going to that site. They can relieve that pressure right now.
"Instead, what they're suggesting is that they will go in and use force to relocate these refugees. And given all the trauma that they've already suffered here at that site, it is quite alarming that they see that as their first option."
Meanwhile, a threat by the PNG prime minister Peter O'Neill to apprehend refugee leaders was also called unacceptable by Mr Boochani.
He said there were no leaders amoung the refugees and that each man has made his own choice to resist eviction.
"The government must take action and solve this problem, not threaten people to arrest them," said Mr Boochani.
"This problem was created by the Australian government. They exiled us by force to this island and they have kept us in this prison camp for more than four years and then they left us. We didn't come to PNG by our will."