In an extraordinary statement issued late last night, Mr Morrison admitted that much of the information he had given to the Australian public since Monday’s riot was now in doubt.

The most explosive admission is the revelation that most of the violence probably took place within the detention centre's fences, rather than outside its boundaries, as Mr Morrison had previously claimed.

“I wish to confirm that, contrary to initial reports received, I have received further information that indicates that the majority of the riotous behaviour that occurred, and the response to that behaviour to restore order to the centre, took place within the perimeter of the centre,” the minister said in the statement.

“In a situation where transferees engage in riotous and aggressive behaviour within the centre, this will escalate the risk to those who engage in such behaviour. However, in such circumstances service providers must conduct themselves lawfully and consistent with the service standards set out in their contract.”

A spokesman for security company G4S, which is contracted to run security on Manus Island, flatly denied to News Corp Australia on Thursday that its staff were involved in the riot, saying: “G4S was not involved in any violence with detainees.”

Fairfax Media was unable to contact G4S on Saturday night.

On Friday, Mr Morrison said the security company would be off the island within a week, when its contract expired.

Transfield, which runs operations on Nauru, will take over security on the island.

The conduct of staff on the night will be investigated as part of the review ordered by Mr Morrison, as well as that of others within the detention centre compound that night.

During the week, Mr Morrison had claimed that the 23-year-old Iranian man killed on Monday night, Reza Berati, had been outside the centre.

“This is a tragedy, but this was a very dangerous situation where people decided to protest in a very violent way and to take themselves outside the centre and place themselves at great risk," he said.

But in the Saturday night statement, Mr Morrison said he had new information that cast further doubt on that claim.

“The precise nature of these events are the subject of the review and police investigation that has been initiated,” he said.

“It will be the task of that review and the police investigation to determine the facts of this incident.”

Labor immigration spokesman Richard Marles said: “It's become very clear minister Morrison has absolutely no idea what has happened and what is happening at the Manus Island detention facility. This should be a great concern to the Australian public.”