Tensions are high in an ongoing stand-off between hundreds of asylum seekers and PNG authorities.

Around 600 asylum seekers are refusing to leave the Manus Island detention centre, which the PNG Government has ordered closed.

Power and water have been cut, food supplies are dwindling but there does not appear to be any break in the deadlock on the way.

Human rights groups have warned the situation could become a humanitarian crisis.

Supporters say about 20 per cent of the men had been on medication for mental health disorders, but that access to their psychotropic medication has been removed.

The Australian Government is building new accommodation facilities, but United Nations High Commissioner for Refugees Nai Jit Lam says his inspections of two of the accommodation facilities revealed that at least one was not ready.

“There's still major works in progress. We saw heavy machinery still in place,” he said.

Human Services Minister Alan Tudge says the new facilities are ready.

“From what I understand there has been people from the Manus Island facility who have been travelling to this other destination on a very regular basis,” Mr Tudge said.

“Sometimes [they go] to do their shopping, sometimes they have already been staying in that new facility and returning at a later stage.”

The asylum seekers have been told that the PNG Defence Force will soon take control of the site, making them liable for removal from an active military base.

Madeline Gleeson - a lawyer and senior research associate at the Kaldor Centre for International Refugee Law at UNSW – says the Australian government is a long way behind in meeting its obligations.