Riots were inside PNG centre: Morrison

Immigration Minister Scott Morrison says the "majority of the riotous behaviour" that killed an Iranian man and injured 62 other asylum seekers on Manus Island this week happened inside the Australian-run immigration detention centre.

An independent investigation into the death of 23-year-old Reza Berati in Papua New Guinea is expected to take several months, but initial reports that the violence took place outside the centre's perimeter already look wide of the mark.

"The further information I have now received casts further doubt on the initial advice that his injuries were sustained outside the centre," Mr Morrison said in a statement on Saturday.

"The precise nature of these events are the subject of the review and police investigation that has been initiated. It will be the task of that review and the police investigation to determine the facts of this incident."

Mr Morrison reiterated his position that it was in the best interest of those held in the centres to "conduct themselves appropriately", but said security workers must also behave properly.

"Service providers must conduct themselves lawfully and consistent with the service standards set out in their contract," he said.

"The independent review established by my department will look at the conduct of the service providers present on that evening, along with any other persons found to be present within the compound that night."

Security firm G4S handed control of the detention centre to Transfield Services on Saturday, with both firms promising to co-operate with the inquiry.

The review will be led by Robert Cornall, who undertook a previous inquiry under the Labor government into sexual abuse allegations on the PNG island.