The Australian government says alternative accommodation to the Manus Island facility is ready and safe.
Immigration Minister Peter Dutton has dismissed claims by the United Nations that alternative accommodation for refugees on Manus Island is not ready.
Almost 600 men have barricaded themselves inside the Papua New Guinea island's mothballed detention centre, a week after it was shut down.
They believe it's safer to remain in the compound than risk being attacked by locals at new facilities near the main township of Lorengau.
The UN's refugee agency says substantive parts of the alternative accommodation were still not ready.
"If the 600 refugees and asylum seekers still in the regional processing centre were to leave it, existing alternative arrangements would not be sufficient for all of them," UNHCR spokeswoman Catherine Stubberfield told The Guardian.
But Mr Dutton said such claims were completely untrue.
"The facilities are completed," he told Sky News on Wednesday.
East Lorengau has been opened for a couple of years and had cost Australian taxpayers millions of dollars, he said.
"We've got security there, we've got health services there," Mr Dutton said.
He labelled claims that refugees and asylum seekers feared for their safety "nonsense", saying it was a "disgraceful and deceitful" myth being pushed by advocates for their own political gains.
"Hundreds of people each day go from the regional processing centre on Manus by bus or walk into the local village, they go shopping, they hang out at the beach, some are in relationships with the locals," he said.
"The fact that somehow security is not provided or there's a problem around security, it's a nonsense."
Papua New Guinea's Supreme Court on Tuesday rejected an application to restore basic services - including electricity, food, medical care and water - to the decommissioned centre on human rights grounds.
The application would also have blocked PNG officials from forcibly evicting the 600 men inside the complex.
The judgment said Australia's legal responsibility for the future welfare of the asylum seekers ended with the closure of the detention centre.
But it also said refugees might be eligible for damages because of the government's "heavy-handed tactics" to force them out of the centre.
Lawyer Ben Lomai, who put forward the original application on behalf of the refugees, is set to file an appeal on Wednesday.
Mr Dutton said the federal government wants to close the centre as quickly as possible and urged those refusing to leave to go.
Nothing they do will change their mind about letting them resettle in Australia, he said.
"We now ask the advocates to stop messaging the people within the regional processing centre telling them not to move, because that is not going to leverage us into changing our position and allowing people to come to Australia."
The immigration minister also appeared to quash any hope of accepting New Zealand's offer to take 150 refugees, insisting it "would be a bad option for us at the moment".