Australia has turned down an offer by New Zealand to take asylum seekers, currently held in limbo, in offshore detention centres in Papua New Guinea where U.N. officials say a humanitarian crisis is unfolding.

About 600 men have barricaded themselves inside the camp on Manus island which Australia wants to close down.

The New Zealand Prime Minister Jacinda Ardern has said her country is willing to take 150 asylum seekers but Australian Prime Minister, Malcolm Turnbull, said he wants to work with the U.S. rather than New Zealand.

“As you know we have an arrangement with the United States whereby a substantial number of 1,250 can, subject to the United States rigorous vetting, be resettled in the United States. And we’re pursuing those arrangements at the moment.”

Food, water and medical services were cut off last week and Ms Ardern says she won’t be withdrawing the proposal.

“We, of course, do not have the circumstances that Australia is operating under, but we also cannot ignore the human face of what Australia is dealing with as well. So the offer is very genuine and absolutely remains on the table.”

Australian authorities want the men moved to a transit centre elsewhere on the island at the start of a process the asylum seekers fear might result in them being resettled in Papua New Guinea.

Meanwhile the U.N. has warned of, what it’s calling an “unfolding humanitarian emergency” in the Manus island centre, where asylum seekers have been reported digging wells to try to find water.