IMMIGRATION Minister Scott Morrison has refused to rule out shutting down the Manus Island detention centre as a damning new report warns Australia is failing in its “duty of care” to detainees in offshore processing centres.

Confirming Australia had sent more than 100 private security officers to Manus since last week’s riots that killed one man and injured 77, Mr Morrison said the possibility of closure was only a “hypothetical”.

Asked if Manus Island was a safe environment he said that was what the contract paid local staff to ensure.

“When people have taken it upon themselves to rip fences down and try and wreck the joint, well, they are going to put themselves at the risk of how people respond,” he told The Sunday Telegraph.

“Now, they are supposed to respond in accordance with their contract and PNG law. If they haven’t, they will face the full force of the law.’’

A report into last year’s $60 million riot at the offshore processing centre on Nauru Island warned that the centre was not secure and could not deal with the riotous behaviour.

A “one model fits all” and “open centre” approach for catering for up to 900 detainees on one site would have a “failed a duty of care test having regard to safety and security issues,” the report, prepared by Keith Hamburger, found.

media_camera Facilities at the Manus Island Regional Processing Facility, used for the detention of asylum seekers that arrive by boat.

Released last night, it found clear intelligence from staff at Nauru was that tensions were building yet officials in Australia believed the risk was “low” and the centre “calm”.

Mr Morrison said he would consider the report’s findings, including warnings that mixed messages to detainees on processing was a significant factor in events leading up to the riots.

He would consider a call to wind back operations in Papua New Guinea if it was recommended by an independent review, but described the suggestion as “hypothetical”.

"There was riotous behaviour throughout the compound and internal fences had been knocked down and the service providers were seeking to restore order."

Although the investigation centres on Nauru it also recommends an urgent review of risk assessment on Manus, where 77 detainees were injured and a 23-year-old Iranian, Reza Barati, died during last week’s violence.

Mr Morrison conceded he was wrong to have suggested Mr Barati had sustained his injuries outside the centre.

Contrary to initial reports of the riots it appeared that his death and most of the injuries had occurred inside the centre.

“There was riotous behaviour throughout the compound and internal fences had been knocked down and the service providers were seeking to restore order,” he said, adding that most injuries were sustained inside the compound.

Mr Morrison also defended the decision of the PNG police to detain arrested asylum seekers in a metal cage, the only jail on Manus Island, with murderers and rapists.

“If you act up in Lorengau, that’s where you will find yourself. That’s the local police cell,” Mr Morrison said.