In a fiery interview on ABC television on Sunday, the Immigration Minister declared "there are facts that I have that you don't" as he refused to resile from his assertions that appeared to blame asylum seekers for last week's violent outburst.

Mr Dutton last week said the Good Friday confrontation came after asylum seekers were spotted leading a five-year-old Papua New Guinean boy into the Australian-run detention centre. The incident caused "a lot of angst" and the mood escalated quickly, he said. PNG police and soldiers fired up to 100 gunshots during the subsequent brawl.

But Mr Dutton's account has been disputed by authorities on the ground, including the Manus Province police commander David Yapu, who said the incident with the child actually occurred a week earlier and had nothing to do with the violence.

The boy - aged 10 not five as claimed by Mr Dutton - was taken into the centre, given some fruit and then escorted out by security. He was returned to his parents unharmed, Mr Yapu said.

But Mr Dutton on Sunday insisted the incident with the child - along with a separate sexual assault - had contributed to a volatile mood on the island. He said he had not been trying to apportion blame but simply to explain why the tensions had boiled over.

"I can give you the facts in relation to it or you can take the Twitter version," he said.

"I was asked why the mood had elevated on the ground on Manus Island. The two incidents fed directly into that. That is indisputable."

Police were investigating the incident involving the child, he said.

"I think that there are facts that I have that you don't so why don't we let the police investigation run its course and allow them some independent analysis ... The parents of the boy involved in the incident might have a different view to the one that you have read off tweets."

Mr Dutton said he had taken advice with senior people on the ground, including the island's governor.

PNG Defence Force chief of staff Raymond Numa, whose soldiers were accused by police of drunken violence in the Good Friday brawl, also said he was not aware of the involvement of a child. Refugees at the facility also denied any link.

The Greens have likened Mr Dutton's claims to "children overboard" - a reference to false claims from the Howard government that asylum seekers threw their children off leaky boats to prompt a rescue.

Tensions are high on Manus after a 28-year-old Pakistani refugee was arrested and charged last month for the alleged sexual assault of a 10-year-old girl in Lorengau.

It was the second sexual assault charge brought against an asylum seeker on Manus Island this year. None have been proven, and both have been contested.

The centre is slated for closure in the latter half of this year after being found unconstitutional by the PNG Supreme Court.