The Prime Minister's intervention on Sunday afternoon came amid mounting pressure on Mr Morrison after he was forced to admit he had misinformed Australians about the violence and death of an asylum seeker in the Manus Island detention centre.

The clashes at the detention centre a week ago - now the subject of an independent inquiry - will come under further scrutiny this week as Parliament resumes and Senate estimates hearings begin.

The Greens and refugee advocates called for Mr Morrison's resignation after he admitted late on Saturday evening that most of the violence, including the death of 23-year-old Iranian man Reza Berati, had probably happened inside the centre, not outside as he had first claimed.

His admission raises questions about the management of the centre by private security firm G4S and doubts about the flow of information to the minister, who made his correction five days after the incident.

Nevertheless Mr Abbott said the Immigration Minister was doing a ''sterling'' job in stopping the boats and had used the best information available to him at the time he made his statements.

''You don't want a wimp running border protection,'' he said. ''You want someone who is strong, who is decent, and Scott Morrison is both strong and decent.''

Mr Abbott added there had been ''very little damage'' to the centre itself during the riot. ''Now, obviously you would rather not have riots, but if there are riots they have to be dealt with and this one was dealt with,'' he said.

Mr Morrison's statement underscored the fact that the spotlight is now on G4S staff, who are responsible for security inside the centre.

While reiterating that detainees were putting themselves at risk by engaging in ''riotous and aggressive behaviour'', he added that ''in such circumstances, service providers must conduct themselves lawfully and consistent with the service standards set out in their contract''.

Mr Morrison said last week that he could guarantee the safety of detainees if they ''remain in the centre and act co-operatively''.

He stood by that remark on Sunday, although he was unable to say whether Mr Berati or any of the wounded detainees had been rioting or behaving aggressively. Asked whether he had confidence in G4S's handling of the incident, Mr Morrison said: ''Well I am going to wait for the review before I draw any conclusions on that front.''

Mr Morrison said he had learnt only on Saturday that he had been wrong in claiming most of the violence happened outside the centre.

David Manne, the refugee lawyer who scuttled the Gillard government's Malaysia Solution, said the government was in breach of the UN Refugee Convention and other obligations under international law.

''Australia's core obligation to asylum seekers is to protect them from harm - an obligation which cannot be met by sending them to Papua New Guinea," he said.

One Liberal MP from the right wing of the party said it was not good enough that it took Mr Morrison so long to confirm a fact as central and basic as whether the violence occurred inside or outside the detention centre. ''I don't know when Morrison found out," the MP said. "But something like this, it should not take the best part of a week to inform the public.''

In a statement on Sunday, G4S stepped back from its previous assertions that its staff had acted professionally. ''G4S will take the strongest disciplinary action against any employee found to have been involved in any wrongdoing against any person in our care, the laws of PNG and our strict code of ethics,'' it said.

with James Robertson