Electricity has so far been cut to half the buildings at the Manus Island detention centre as refugees refusing to leave nervously await their future.
Australia's offshore immigration centre at Lombrum Navy Base was officially closed on Tuesday.
However authorities face a stand-off with detainees unwilling to go and locals are reportedly blocking the construction of new refugee accommodation.
The more than 600 refugees and asylum seekers who remain inside the compound in Papua New Guinea have little water left and their electricity generators have either been switched off or let run out of fuel.
The last food packs were distributed to them on Sunday night.
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Tamil refugee Srirangan told AAP on Tuesday refugees were concerned about dehydration but feared for their lives as well, with troops from PNG expected to arrive on Wednesday.
He said the buildings has also become too hot to be in and "many of us are outside ... and will have to sleep on the ground".
Another Tamil refugee, Ravi, told AAP by phone detainees were trying to collect water in bins and containers but "there had been no rain".
Authorities in PNG have said they will move refugees and asylum seekers into purpose-built accommodation in the nearby town of Lorengau.
Hussein, originally from Iraqi Kurdistan, said the facility wasn't ready and that locals had blocked and protested its' construction.
He added that some had looted tents, tables, boxes, fire alarms, fans, air conditioners and "whatever they saw" from Manus on Tuesday.
PNG lawyer representing the detainees, Ben Lomai, said he lodged a legal application to block the centre's closure on Tuesday.
The constitution in PNG held enforceable protections for human rights, which Mr Lomai said had been breached.
Greens senator Nick McKim is on the island and spoke with centre occupants on Tuesday afternoon.
"They still believe that despite everything that's happened to them at the detention centre it remains the least unsafe place for them to be," he said, adding that he believed there was still a 150-bed shortfall at alternative facilities.
The Lombrum centre was forced to close after the PNG Supreme Court ruled in April 2016 that Australia's detention of refugees and asylum seekers there was illegal and unconstitutional.
Six detainees have died on Manus Island - including one who was murdered - since it was reopened in 2012.
A Human Rights Watch report last week detailed cases of refugees allegedly being stabbed and robbed in the town while trying to visit the supermarket.
Extra PNG police and defence forces had been flown into Manus.
Local media has reported PNG Immigration Minister Petrus Thomas as saying the detainees won't be forced to leave the centre.
Acting prime minister Julie Bishop maintained refugees and asylum seekers on Manus Island will be guaranteed all appropriate services at their alternative accommodation.
Immigration Minister Peter Dutton had little sympathy for those left.
"They have long claimed the Manus (centre) was a hellhole but the moment it was to be closed they demanded it be kept open," he said.
Labor's immigration spokesman Shayne Neumann urged the government to urgently de-escalate tensions and ensure safety.
"Transferring refugees from one centre to another is not a long-term solution. These people urgently need viable third country resettlement options," he said.
Amnesty International's Kate Schuetze, who is on Manus to observe the closure, said PNG police and defence forces had a history of violence against refugees.
Ms Schuetze pointed to the Good Friday shooting, when nine people were injured after PNG military personnel opened fire on the Manus Island centre.
PNG's government has warned Australia it will take no responsibility for "non-refugees" and people who refuse to settle in PNG, saying they are the obligation of Australia.
The Lombrum centre was forced to close after the PNG Supreme Court ruled in April 2016 that Australia's detention of refugees and asylum seekers there was illegal and unconstitutional.
Six detainees have died on Manus Island - including one who was murdered - since the detention centre was reopened in 2012.
