An Australian senator is warning today's closure of the Manus Island detention centre could end in tragedy.
The Papua New Guinea navy is due to take control of the centre where water, food and electricity are scheduled to be cut.
But about 700 refugees detained there by Australia plan to peacefully resist relocation.
Iranian detainee Farhad Rahmati said the refugees would not leave voluntarily.
"If the choice is between dying here or dying in our own countries then on the 31st of October we will take the only real choice we have left. We'll stand side by side as brothers and peacefully refuse to leave the Manus RPC."
The PNG government said it would not to use force to move the refugees to three buildings in the island's main town.
But senator Nick McKim said with a police paramilitary squad on standby for the closure, a violent confrontation was possible.
"What transpires over the next 48 to 72 hours unfortunately is anyone's guess and it's very hard to predict. But I've got grave fears that we are heading down a path towards tragedy and a humanitarian emergency here on Manus Island."
Senator McKim said only one of the buildings seemed ready to house the refugees.
"There's the East Lorengau Transit centre, which the Australian government has recently jammed a large number of extra beds into. So they're proposing that people quadruple bunk in tiny little cells and that place is effectively a prison. The other two facilities are not yet complete," he said.
"So the Australian government has just got to calm down, immediately abandon plans to cut off life supports into the centre because there is simply no safe option for these guys at the moment.
"And that's why they, as a matter of urgency, need to be evacuated out of Papua New Guinea and delivered to the US, or to New Zealand, or to Australia."
The PNG government said Australia needed to find other countries to take the refugees.
It also raised concerns about reduced health care services in the new buildings.
Mr Rahmati said that would cause more refugee deaths.
"There are some of us who will die from treatable and preventable illnesses. There are some of us who will be attacked by angry locals. And then there are some of us who will eventually take our own lives. Until then all of us will live a life of poverty and fear in a place where we are not welcome."
From Manus, Amnesty International's Kate Schuetze said local Manusians had prepared a petition opposing the relocation.
She said they too were afraid PNG police could be heavy handed.
"Locals are telling us PNG police are coming in armed to the hilt like they're going to fight a war. So it is a very concerning situation, I think everyone is on edge," she said.
"And the locals cannot understand why Australia has treated these people this way and locked them up for so many years and now just wants to withdraw and leave them here."
Senator McKim said Manusians could react violently to the relocation.
"There's a high degree of concern in the local community and understandably so. About 600 men from the other side of the world with very different cultures are basically being dumped into the community," he said.
"The refugees are also scared about what might happen if they are forcibly transferred into the community because there have been multiple knife and machete attacks on refugees by locals in the last few months.
"So everywhere these guys look they are faced with danger and they are legitimately and understandably in fear for their lives."
Lawyers yesterday filed an application to the PNG Supreme Court which could delay the closure. They are hoping the application will be heard today.