PNG police commissioner David Manning addressed the media on Friday night saying the 750kg of cocaine was to be transported aboard a plane which crashed at Papa Lealea outside Port Moresby on Sunday.
The crash exposed a Melbourne-based crime syndicate and resulted in the arrest of five men who allegedly had links to the Italian mafia, the report says.
Authorities said the plane had flown to Papua New Guinea from the small town of Mareeba in Far North Queensland, flying at about 3,000 feet to avoid detection by radar.
The Cessna aircraft, which was stuffed with more than 500 kilograms (1,100 pounds) of cocaine, went down while attempting to leave a remote airstrip in Papua New Guinea on July 26.
"The AFP (Australian Federal Police) alleges greed played a significant part in the syndicate's activities and can not rule out that the weight of the cocaine had an impact on the plane's ability to take off", the police said in a statement.
The country's prime minister, James Marape, said at the time he suspected it was used for drug trafficking and asked Australian authorities to help uncover the mystery.
Five men were arrested and now potentially face life imprisonment.
Police said the five men were arrested in Queensland and Victoria on Sunday, on allegations that they meant to carry out the importation and collection of cocaine from Papua New Guinea estimated to be worth more than $80 million.
Police in Papua New Guinea have seized $86 million worth of cocaine they believe was destined for Australia. He was arrested and has been charged with an immigration offence.
These include three properties, shares, account funds and a vehicle.
Two other men, aged 33 and 61, faced Melbourne Magistrates Court on the same day charged with conspiring to import commercial quantities border controlled drugs.
The light plane heading for Australia was allegedly laden with so much cocaine it was too heavy to take off, police say.
"These arrests prove no matter how sophisticated or opportunistic organized crime's attempts are, or the methods they use, law enforcement is keeping pace and causing maximum damage to these criminal ventures", McCartney said.