The Colombian Navy has seized 225 tonnes of cocaine during a six-week operation and says it uncovered a new drug trafficking route operating from South America across the Pacific Ocean to Australia.
The latest phase of the bust, titled 'Orion', resulted in more than 1,400 tonnes of drugs including 128 tonnes of marijuana being seized at a street value of more than $US8.4 billion ($12.9bn), according to Colombian navy official Orlando Enrique Grisales.
More than 400 people were arrested in the operation targeting oceans, coasts, rivers and ports around the globe in October and November.
The operation also involved the national security agencies of countries like the United States, Brazil, Spain and the Netherlands in partnership with other international organisations.
The Colombian Navy has intercepted a semi-submersible vessel in the Pacific Ocean during a major drugs operation. (Supplied: Colombian Navy)
Vice-admiral Grisales said officials also seized a semi-submersible vessel made of wood and fibreglass on its way to Australia with five tonnes of Colombian cocaine onboard.
This was the third such vessel discovered in the Pacific Ocean, revealing a "new route" of trafficking with sophisticated boats that can cover the distance of some 10,000 miles without needing to refuel, according to Colombian authorities.
Commander of the Colombian Navy, vice-admiral Juan Ricardo Rozo, told media outlets in Colombia the authorities of nations targeted by drug cartels in the new trafficking routes had been alerted to the arrests.
"[Drug cartels] are dedicated to trafficking, everyone wants to have control, they fight over it and there is participation from all the armed groups and organisations that work with drug trafficking," vice-admiral Rozo told Colombia's W Radio.
"Semi-submersibles are not a new practice, but they have been developed to reach more distant places.
"We have discovered routes such as Australia and Guyana to open up through the Atlantic to Africa and connect to Europe."
Colombian authorities say they have uncovered a new drug trafficking route used by cartels between South America and Australia across the Pacific Ocean. (Supplied: Colombian Navy)
The Australian Federal Police told ABC News in a statement that it has no comment on the operation. The Australian Border Force did not provide ABC News with a response.
A kilogram of cocaine is sold for up to $240,000 in Australia — about six times more than the price in the United States, vice-admiral Grisales said.
"It is a route that is becoming increasingly profitable because prices are much higher in Australia," a security source told AFP.
"Initially, these boats were used mainly to take the drugs out of the country and move them off the coast of Colombia and then transfer them to ships.
"It has been found that these semi-submersibles, sometimes even submersibles, are now increasingly sophisticated, with very fine engineering."
The operation uncovered previously-unknown alliances between drug cartels from Mexico, Brazil, Colombia, Ecuador and Peru along with groups from Europe and Oceania, according to vice-admiral Grisales.
"It is not just a pyramid structure as the cartels once were. Today they are organised crime networks joined together," vice-admiral Grisales said.
Colombia is the world's biggest cocaine producer and exporter, mainly to the United States and Europe.
Last year, the South American country set a new record for cocaine production and cultivation of the coca leaf it is made from.
ABC/AFP