Papua New Guinea Defence Force personnel allegedly fired shots into the centre after a fight with asylum seekers, Immigration Minister Peter Dutton said.
Mr Dutton then said the incident was the result of three asylum seekers allegedly leading a local five-year-old boy back towards the facility.
But local police accounts differed from Mr Dutton's, while former Manus Island MP Ronny Knight appeared on the ABC, where he said the violence was unrelated to the fact a child had been taken into the centre.
Mr Knight was dismissed from office two years ago, over charges of misappropriating funds.
"What I said is factual, I stand by it 100 per cent, and I'm not going to be cowered into a different position when I know what I've said to be the truth," Mr Dutton told Sky News.
"I'll stand by those comments and I expect the ABC and Fairfax and others to be making an apology in the next 24 hours, given the revelations that have been released tonight in relation to their discredited witness."
Mr Dutton said he has information that hasn't been made public. He stuck to his guns, accusing journalists of becoming "advocates", and at the same time, welcoming what he calls "more substantive views".
"The problem is, in relation to a lot of journalists, they've morphed into advocates and lost control of any dispassionate view of this circumstance," Mr Dutton said.
"If somebody from the ABC, or from Fairfax, or The Guardian, or some of these fringe dwellers out on the internet have a different view, a more substantive view, or more informed view, let them put it on the table.
"But I have relayed the facts as they have been provided to me by my department, and those people with knowledge of what happened on the ground, and I'm not changing my position, my version, one bit."
Peter Dutton on Manus shooting
