"We call on the Australian government. who interned the men in the first place to immediately provide protection, food, water and other basic services", United Nations rights spokesperson Rupert Colville told a news briefing.
Meanwhile, the situation on the remote Manus island in Papua New Guinea, or PNG, is growing more serious with around 600 refugees barricading themselves inside the camp, defying efforts by Australia and PNG to shut it. Food, running water and medical services were cut off by Australia five days ago.
"Refugees and non-refugees should no longer have any security concerns", he said.
"We thank New Zealand for making an offer, we are not taking it up at this time". "We urge the Australian Government to transfer the men to mainland Australia where their claims can be processed".
Ms Ardern said the "very genuine" offer would remain on the table. The men have been told to leave, but fear they will be attacked by members of the local community who do not wish for them to settle in PNG.
Ardern said in a statement the offer would be covered by New Zealand's existing refugee quota and applied to offshore refugees on both Manus Island and the tiny Pacific island nation of Nauru.
United Nations rights spokesman Rupert Colville told a news conference in Geneva on Friday about the "unfolding humanitarian emergency" in the Manus island center, where asylum seekers have been reportedly digging wells to try to find water. They are Rohingya Muslims from Myanmar, Afghans, Iranians, Sri Lankans and other nationalities.
For four years, Australia has paid Papua New Guinea, its nearest neighbour, and Nauru to house asylum seekers who attempt to reach the Australian coast by boat.
Her Australian counterpart, Malcolm Turnbull, however said Canberra preferred to work through an existing refugee swap deal he negotiated with former U.S. President Barack Obama previous year. "They force us to starve".
However, during a bilateral meeting in Sydney with his counterpart Jacinda Ardern on Sunday, Mr Turnbull said his government was focused on a United States resettlement deal to take up to 1250 people.
Donald Trump called it a dumb deal but Malcolm Turnbull says the U.S. agreement to take 1250 refugees from Australia is his priority over New Zealand's offer to help 150. "You can't keep political hostages".
'We should give consideration to what New Zealand is offering, ' he told Sky News on Sunday. So far, about 50 refugees have been settled under the deal.