Human rights group Amnesty International says the Australian government deliberately downplayed the danger asylum seekers on Manus Island faced in an attack by Papa New Guinea soldiers last month.
Amnesty said video from the incident showed bullets were fired directly into the detention centre, contradicting Australian government claims.
It said it had analysed photos and videos that showed bullets were fired into the accommodation area of the centre that night - directly contradicting the government's claims that they were fired into the air.
"I think we can say with a degree of certainty now that multiple shots were fired into the centre and that put people at risk," researcher Kate Schuetze said.
"It's ... the second time now that the centre has been under attack from the outside, which really proves that the Australian government and the Papua New Guinean government cannot protect the safety of refugees and asylum seekers there."
The human rights group said it had analysed 21 photos and six videos purportedly taken from inside the centre the night of the attack.
"The digital experts used reverse image search tools and corroboration with known photos of the centre to geolocate the images," the report said.
"A military expert also reviewed the images and videos."
Ms Schuetze said it appeared the government had sought to minimise the perceived risk to asylum seekers.
"We've had a lot of information come out very quickly, trying to downplay not only the incident and the risk that refugees were put in, but also to try and deflect attention from the actual causes around what happened," she said.
Grant Bayldon from Amnesty's New Zealand office discusses the incident
'Ultimately a matter for PNG government'
The Department of Immigration and Border Protection said Amnesty International did not consult it about the report or seek a response.
"Consistent with previous Amnesty International reports, the Department has not been consulted nor provided an advance copy of this report," it said in a statement.
"While this is ultimately a matter for the PNG government, we cannot comment on a report we have not seen."
PNG police and defence force were separately investigating the attack.
There are more than 800 men in the Manus Island detention centre, and roughly another 80 living in the transit centre or elsewhere in PNG under a resettlement agreement.
Of those, about 700 have been found to be refugees and are eligible for resettlement in the United States or PNG.
There were 160 men in the centre whose refugee claims failed.
-ABC