Two men are behind bars, accused of a botched attempt to retrieve more than half a tonne of cocaine dropped overboard from a bulk cargo carrier off the Western Australian coast.

Australian Federal Police says the audacious plan came undone when a 45-year-old man got into trouble and needed rescuing from his seven-metre fishing boat on August 7, off the Western Australia coast at Denham.

Two Queensland men have now been extradited to WA, charged over their alleged involvement in the bust worth more than $200 million, which the AFP says was organised by a transnational drug trafficking criminal syndicate.

The second man, a 53-year-old who also travelled to WA, was waiting at a boat ramp for the drugs to be retrieved by his partner, with a plan to drive the drugs back to Queensland, police said.

Four days later federal and WA police officers raided a Kalbarri property, 570km northwest of Perth, where they found about 560kg of cocaine wrapped in plastic.

Both men were handed over to WA police after facing a Mackay court last month on charges of attempting to import a commercial quantity of cocaine.

Australia, a prime market

Had the cocaine made it to the streets, it could have been sold as about 560,000 individual street deals, AFP Inspector Chris Colley said on Sunday.

“That would have resulted in an estimated $224 million spent on purchasing cocaine rather than at legitimate local businesses,” he said.

Drug syndicates target Australia due to its high demand which makes it a profitable market, with 2.3 tonnes worth of drugs stopped by authorities this year, he said.

The two men will appear in court on January 12, 2024, where they face a maximum penalty of life imprisonment.

Three other men from Queensland were also arrested at the Kalbarri property with police alleging they had bought a boat and used it to collect the cocaine from the ocean.

Those men, aged 29, 32 and 49, remain before the courts.

Border Force authorities have busted more than 4200 cocaine deals with an estimated total weight of 4769kg in 2022/23 financial year, representing a 166 per cent increase from the previous financial year, ABF Commander Ranjeev Maharaj said.

“Organised crime syndicates are relentless in their efforts to flood our shores with cocaine, with the motivation being greed and profit,” Commander Maharaj said.

-with AAP