Three 'narco-submarines' are seized along with drugs worth $8 billion

Three 'narco-submarines' trafficking $8 billion worth of drugs from South America to Australia have been intercepted by the Colombian navy in what was a a six-week-long global drug bust.

The latest phase of operation 'Orion' resulted in the seizure of 1,400 tons of drugs, including 225 tons of cocaine and 128 tons of marijuana, navy official Orlando Enrique Grisales told reporters in a press conference on Wednesday. 

More than 400 people were arrested in the crackdown in October and November that involved the security agencies of the United States, Brazil, Spain, the Netherlands and several other nations.

Grisales said officials also seized a semisubmersible vessel on its way to Australia with Colombian cocaine, revealing a 'new route' of trafficking with sophisticated boats that can cover the distance of some 10,000 miles without needing to refuel.

'The first was discovered in Colombian watersm and thanks to the maps it carruedm we identified the route', Grisales said. 

The last submarine to have been intercepted during the bust was found off the coast of Clipperton Island in the eastern Pacific. 

A kilogram of cocaine is sold for up to $240,000 in Australia, said the official - about six times more than the price in the United States.

The operation also uncovered previously-unknown alliances between cartels from Mexico, Brazil, Colombia, Ecuador and Peru with groups from Europe and Oceania.

'It is not just a pyramid structure as the cartels once were. Today they are organized crime networks joined together,' said Grisales.

Colombia is the world's biggest cocaine producer and exporter, mainly to the United States and Europe.

Meanwhile, Australians are the highest per capita users of cociane in the world, according to the OECD. 

Last year, the South American country set a new record for cocaine production and cultivation of the coca leaf it is made from.

It comes after Royal Navy commandos intercepted a narco-sub and seized two-tonnes of cocaine worth a staggering £1600 million back in September. 

Royal Marines based on patrol ship HMS Trent made the historic bust during a patrol in the Caribbean.