Asylum seekers and refugees at the Manus Island detention centre have been digging into the ground overnight in an effort to find water.
The stand-off between the 600 men inside the detention centre and immigration authorities is entering its second day.
Water, power and food supplies to the detention centre were cut off after its official closure on Tuesday.
Photos taken by Kurdish-Iranian refugee and journalist Behrouz Boochani show men digging into the ground overnight to find water.
He tweeted, "it's a tropical area and people think they will reach fresh water".
In a final notice posted by immigration authorities on Sunday night, the men were told the PNG Defence Force would start to take control of the site from Wednesday.
It warned the men that anyone choosing to remain would be liable for removal from an active military base.
The asylum seekers, warned that utilities would be cut, had begun to collect rainwater in bins.
However without running water, advocates fear a rapid decline in sanitary conditions of the camp.
The detainees were sharing what food remained, but some of the men Reuters spoke to by phone said supplies were running low.
They had been given enough meals to last only until the camp's official closure on Tuesday.
Human Services Minister Alan Tudge yesterday rejected claims alternative facilities meant to accommodate the men were still being built.
The United Nations High Commissioner for Refugees, Nai Jit Lam, is on Manus monitoring the effort to move the men from the detention centre.
Earlier this week, Mr Lam inspected two of the accommodation facilities the men are supposed to be moved to and said one, called West Lorengau Haus, is not ready.
"There's still major works in progress. We saw heavy machinery still in place," he said.
Acting Prime Minister Julie Bishop said the men should move to the new centres, which Australia has said it would support with $250 million worth of food and security for the next 12 months.
Acting Opposition Leader Tanya Plibersek said the situation had been "poorly handled".
"I am worried about what looks like a developing powder keg and I won't pretend I'm not worried," Ms Plibersek said.