SYDNEY (REUTERS)- The United Nations refugee agency on Tuesday (Nov 14) urged Australia to accept New Zealand's offer to resettle 150 refugees from an abandoned Australian-run detention centre in Papua New Guinea, as about 450 men remain barricaded inside without food or water.

The asylum seekers have been holed up inside the centre for the past two weeks defying attempts by Australia and Papua New Guinea to close the facility, saying they fear for their safety if moved to transit centres.

With many detainees complaining of illness bought about by the unsanitary conditions inside the camp, the United Nations High Commissioner for Refugees (UNHCR) urged Australia to allow 150 of them to resettle in New Zealand.

"We urge Australia to reconsider this and take up the offer," Nai Jit Lam, deputy regional representative at the UNHCR told Reuters. The asylum seekers are mainly from Afghanistan, Iran, Myanmar, Pakistan, Sri Lanka and Syria.

Australian Prime Minister Malcolm Turnbull earlier this month rejected a refugee resettlement offer from his New Zealand counterpart Jacinda Ardern, preferring instead to work through an existing refugee swap deal he negotiated with former United States President Barack Obama last year.

Under that deal, up to 1,250 asylum seekers detained by Australia in Papua New Guinea and Nauru in the South Pacific could be resettled in the US in return for Australia accepting refugees from Central America. So far, the US has accepted only 54.

Despite Turnbull rejecting the offer, Ardern this week said the offer remained on the table and that she would seek a second meeting with Turnbull to discuss the "unacceptable" situation inside the Manus island detention centre.

Running water and electricity to the Manus island detention centre were disconnected two weeks ago after Australian security withdrew and the camp closed on Oct 31. The centre had been declared illegal by a Papua New Guinea Court.

Papua New Guinea has threatened to forcibly move the men if they remain inside the centre. It has set three deadlines but all have passed largely without incident.

Australia's "Sovereign Borders" immigration policy, under which it refuses to allow asylum seekers arriving by boat to reach its shores, has been heavily criticised by the UN and human rights groups but has bipartisan political support in Australia.

Australia says allowing asylum seekers arriving by boat to reach its shores would only encourage people smugglers in Asia and see more people risk their lives trying to sail to Australia.