Traffickers smuggling illicit drugs into Australia by ship have been put on notice by senior federal police following a spate of major busts, rescue calls and a death.
Criminals are increasingly turning to "at sea" imports, where illicit drugs are smuggled into Australian waters on ships and dropped in the ocean for retrieval by local crews, according to AFP Crime Command Detective Superintendent Anthony Conway.
Hiding the drugs on the hull of a cargo ship under the waterline or inside the vessel's sea chest cavity where divers submerge to retrieve the goods was also common, he said on Sunday.
Authorities are on high alert and have thwarted several plots in the past year with several people needing to be rescued after hitting trouble on the water.
The rescues highlighted the lengths criminals would go to in their attempts to bring drugs into Australia for their own greed and profit, Det Supt Conway said.
"We have seen instances of people who are not experienced with boats purchasing small vessels and heading out to sea in windy, rough conditions or in the dark," he said.
A diver was found dead in a NSW harbour last year with police suspecting he was trying to retrieve packages of cocaine from a bulk carrier.
Three men had to be rescued from the ocean off Western Australia's Great Southern region in February after their cabin cruiser capsized in rough seas.
The trio said they had been fishing but were later arrested and charged after police found the boat they had been on was damaged with about 300kg of cocaine inside.
Authorities were again called to the aid of three men off the coast of Fremantle in May after they struck trouble in the 10m cabin cruiser they had bought only a day earlier.
Police linked the men to the attempted collection of almost 850kg of cocaine imported on a bulk cargo carrier.
A 45-year-old man then got into some late-night trouble in August and needed rescuing from his seven-metre fishing boat while trying to retrieve a consignment of cocaine off the coast of Denham, 840km northwest of Perth.
Divers retrieving drugs from the hull of cargo ships are in immense danger because it usually involves diving at night in busy shipping channels with unpredictable tidal conditions, Det Supt Conway said.
"Anyone involved in these at-sea trafficking enterprises is not just risking their freedom - they're also risking their life."
Authorities have been working with international law enforcement partners to prevent transnational drug syndicates from hijacking cargo supply chains for their criminal distribution networks.
More than 26 tonnes of illicit drugs and precursors were blocked from reaching Australia in the 2022/23 financial year.
"Illicit drug use in Australia bankrolls dangerous and brutal criminals who undermine our national security and our economy and make our suburbs and roads less safe," Det Supt Conway said.
Several people allegedly linked to the syndicates have been arrested in Australia and overseas.
Australian Border Force Commander Ranjeev Maharaj said there had been a marked increase in cocaine detections this year, almost more than the previous two years combined.