Papua New Guinea Police believe they have recovered all the bodies following last Thursday's plane crash which killed 28 people.
The Ministry of Civil Aviation says mechanical fault appears to be the most likely cause as to why the Airlines PNG Dash-8 aircraft crashed about 30 kilometres south of Madang town.
The plane's black box voice recorder has been sent to Australia for analysis.
The Provincial Police Commander, Superintendent Anthony Wagambie, says the formal identification of 27 bodies may take up to a month.
"It's a slow process. I have been advised by the team leader from the Australian Federal Police that it may take some time because of the bodies' state and the tests which have to be done."
Superintendent Anthony Wagambie.
He says police are still keeping the crash site secure as investigators continue their work.
