A yacht that washed up on a deserted island in the South Pacific with a badly decomposed body on board was carrying more than 200 kilograms of cocaine worth up to $120 million, police said on Friday.
Australian Federal Police said international law agencies had been monitoring the 13-metre (42-foot) yacht "JeReVe" from when it left South America until they lost contact with it last month.
Two divers came across the boat earlier this month off Tonga's Vava'u island group and made the grim discovery of the dead Caucasian male when they went aboard. They then reported their find to police.
"Also located on board that vessel were 204, one-kilo (2.2-pound) blocks of cocaine destined for the Australian market," acting national manager for serious and organised crime David Sharpe told a press conference.
The massive seizure, with an estimated Australian street value of up to Aus$116 million, was now part of an ongoing operation involving police in Tonga, the Cook Islands, Australia and the US Drug Enforcement Administration.
Australia has provided forensic services to help identify the body, which is subject to an inquiry by coroners in Tonga.
Police in Tonga, a small Pacific island nation close to the international dateline, have not ruled out the possibility that the death was suspicious but said it remains "an unexplained death".
The yacht, which Tongan authorities were unable to search initially because of difficult tidal conditions and its remote location, was eventually found to be carrying the drugs in its hull.
Australian authorities were first alerted that a vessel loaded with cocaine was en route from Ecuador in August by US authorities with whom they are working to target global organised crime syndicates using the South Pacific.
When information suggested the yacht was in waters near the Cook Islands, police there were also brought into the investigation.
Sharpe said the cooperation between Australia and its Pacific neighbours demonstrated the reach of law enforcement.
"And while we can state that those drugs were not destined for Tonga or the Cook Islands, Tonga and Cook Islands played an integral part of this investigation, which started in South America," he added.
Australian Customs said there had been three other major seizures in the Pacific in the past two years, twice within Australian waters and once in New Caledonia.
"The South Pacific is a huge expanse out there," said Customs' acting national manager for enforcement operations, Neil Sugget.
"Clearly no one is responsible for the whole Pacific. Everybody has to play their part. We've got no choice but to get out there and work with every other country in a cooperative manner."
In late 2010, Australian Federal Police said they had arrested four men in Sydney over a plot to smuggle almost 700 kilograms of cocaine into the country via Tonga.