The Cessna aircraft came down shortly after taking off from a remote airstrip on the south coast of Papua New Guinea last Sunday.
It was found abandoned and empty but officials recovered 28 bags of drugs weighing a total of 500kg at a different location on the island.
Australian Federal Police (AFP) announced on Saturday they had charged five suspected drug traffickers with alleged links to Italian organised crime. They face life imprisonment if convicted.
The pilot, also Australian, was arrested and charged with an immigration offence after handing himself into the embassy in Papua New Guinea.
Officials described the attempt to smuggle the cocaine into Australia during the coronavirus pandemic as “brazen”.
“With current interstate travel restrictions in place due to COVID-19, the attempt to import illicit drugs into Australia shows how opportunistic and greedy organised crime can be,” said AFP Deputy Commissioner Investigations Ian McCartney.
“Australian law enforcement remains committed to working collectively to protect Australia, which is especially important now, due to the ongoing impact of the pandemic on the community.”
Police said the Melbourne-based crime syndicate arranged a flight from Marreeba in Queensland to Papua New Guinea on the morning of 26 July to collect the cocaine.
It is alleged the light aircraft flew at an altitude of only 3000 feet in an effort to avoid radar detection.
After picking up the drugs, it crashed while attempting to take off from an area norther of Port Moresby that afternoon.
“The AFP alleges greed played a significant part in the syndicate’s activities and cannot rule out that the weight of the cocaine had an impact on the planes ability to take off,” the police said in a statement.
Photos released by police also showed a recovered drug package marked with ‘777’ and hiding spaces within a truck.