Asylum seekers on Manus Island have been told they must leave the Australian-funded detention centre so it can be closed.

Key points: Refugees have option of relocating to transit centre, settling in PNG, or returning to countries of origin

Refugees have option of relocating to transit centre, settling in PNG, or returning to countries of origin Men whose claims have been rejected told to return to countries of origin by end of August

Men whose claims have been rejected told to return to countries of origin by end of August Refugee says many detainees will not accept closure

Papua New Guinea immigration officials told the more than 800 men in the detention centre that demolition work would start soon on parts of the accommodation.

The ABC has received a recording of an unnamed official addressing detainees inside the centre on May 15.

"You cannot stay at the regional processing centre," he said.

"You need to consider your options. No-one will be resettled in Australia."

The 700 men found to be refugees have been told they have the option of temporarily relocating to a so-called "transit centre" near the main town of Lorengau, settling in the PNG community, or returning to their countries of origin.

The remaining men whose claims have been rejected have been told they should agree to return to their countries of origin before the end of August, when a $20,000 cash incentive from the Australian Government will cease.

"Everyone will need to move out of RPC (Regional Processing Centre) before it shuts down," said the official.

"Do not leave it too late to make a decision."

Refugees' future uncertain

The announcement comes despite continuing uncertainty about the fate of those found to be refugees.

Only some of them will be accepted for resettlement in the United States under a deal agreed with the Obama administration.

But the immigration official told detainees they should see the centre's closure as a good thing.

"Closure of the regional processing centre is an opportunity to get on with your life," he said.

The detainees have been told the Foxtrot accommodation compound, which houses at least 200 men, will close by the end of June.

One of its accommodation blocks will close by May 28 and will be demolished.

A small number of men already live in the transit centre in East Lorengau, but they complain of being targeted by criminals and harassed by angry local residents.

Iranian refugee Amir Taghinia said that had made many of the detainees afraid to follow them.

"They are facing daily attacks, they get beaten up, they get robbed and there is a bit of, not a proper treatment in the town," he said.

"There is a bit of [a feeling] like, those people were dumped into the town."

Refugee predicts 'big riot'

The men in the detention centre are being told that the closure of the centre is inevitable — that compounds will be cleared and locked and the electricity shut off.

What is the US-Australia agreement? Agreement would cover people on Manus Island and Nauru found to be genuine refugees.

Agreement would cover people on Manus Island and Nauru found to be genuine refugees. Depending on how many pass US's "extreme vetting" process, the ABC understands the offer would be made to the vast majority of people still in offshore detention centres, as well as those processed offshore but are currently in Australia due to medical reasons.

Depending on how many pass US's "extreme vetting" process, the ABC understands the offer would be made to the vast majority of people still in offshore detention centres, as well as those processed offshore but are currently in Australia due to medical reasons. The offer would not be made to those who have accepted resettlement elsewhere.

The offer would not be made to those who have accepted resettlement elsewhere. Federal Government has said it would prioritise families first.

Iranian refugee Behrouz Boochani said many detainees would not accept that.

"I am sure the refugees will resist and they will have to use force, I think there will be a big riot," he said.

The men who have been found to be refugees have the option of living in Port Moresby or another urban centre while they wait to see if they will be resettled in the United States.

PNG immigration officials told the asylum seekers they would still be interviewed by US Government representatives if they were not in the detention centre.

But none of those living outside the centre have been interviewed so far, and there are still hundreds of men inside waiting as well.

Mr Boochani said this latest announcement seemed like another attempt to make the refugees resettle in Papua New Guinea, and it would be rejected.

"We want to say to people and to the government, we don't want to live in PNG," he said.

"Don't use force and don't make trouble in this island. It is enough."