A PNG immigration official, believed to be centre co-ordinator Jeffrey Kiangali, told asylum seekers on Monday: "PNG, with Australian support, will close the Manus RPC [regional processing centre] by October 31, 2017".
"The centre won't close drop dead on the 31st of October, they will start to decommission parts of the centre in the run up", he told local radio 3AW on Tuesday.
There is a possibility some detainees may die as a result of the announcement.
Refugees awaiting acceptance for resettlement by the United States will be relocated to the East Lorengau Refugee Transit Centre and given the option to return home with assistance, or to move to another country where they have the right to reside.
"They could. go back to the countries they have fled from and face persecution, personal danger, arbitrary imprisonment or worse", Senator McKim told reporters in Hobart on Tuesday.
But the immigration official told detainees they should see the centre's closure as a good thing.
The 20 percent whose applications were denied were told they must return to their home countries; if they do so voluntarily, they will get 25,000 dollars from the Australian government; if not they will be sent back home anyway.
The immigration officer said: "In coming months, other compounds will be closed and demolished".
"Manus prison is full of tension", Boochani, wrote in his next tweet.
"I am sure the refugees will resist and they will have to use force".
He told the ABC he expected there to be riots.
The governments in Port Moresby and Canberra have struggled to come up with a plan for Manus ever since the PNG Supreme Court ordered the facility closed past year.
Plans for the centre's gradual closure were released this week by Papua New Guinea authorities and the leaked documents show that for a year companies have been trying to make settling in the PNG community a more attractive option for refugees than remaining at the centre.
An unspecified number of asylum-seekers will be relocated to a transit center, one refugee quoted the officials as having said.
Manus Island and Nauru asylum centres have been condemned by human rights groups and the United Nations for cramped conditions, violence and inadequate medical facilities.
Mr Dutton has repeatedly stated PNG soldiers opened fire on the centre because they were concerned about the welfare of a young boy who was allegedly led into the compound.
It is still unclear when the resettlements will begin but Mr Dutton says the U.S. are putting no roadblocks in the way.
'For him then to try and connect (the incident involving the boy), weeks later, to drunken soldiers shooting at a refugee centre is reckless in the extreme and will put the lives of people there at even greater risk'.