The drugs were found on a yacht in a Vanuatu port, hidden underneath concrete that required a chisel to cut through. The cocaine is estimated to be worth about $370 million.

Australian Federal Police agents joined Australian customs concealment experts and US officials in Port Vila on Monday to examine the massive drug bust, one of the largest involving Australian law agencies.

The boat, known to authorities as the Raj but renamed Scope, was docked and no one was on board when the seizure was made.

No one has been arrested. Authorities said the boat was for sale when it was raided.

The drug bust is the largest made under Project Cringle, an operation set up in 2010 by the AFP, Australian Customs and Border Production and the US Drug Enforcement Administration to target criminal organisations using the South Pacific as a transit point and staging area.

Customs Compliance and Enforcement national director Karen Harfield said there was a sophisticated concealment of the drugs in the lower engine compartments and around the keel area of the hull.

“Certainly the coverage made it particularly difficult - the actual ability to access the gaps where the drugs could be concealed meant you had to use a chisel, rather than being able to open compartments or pull compartments apart,” Ms Harfield said.

The AFP Serious and Organised Crime national manager, Assistant Commissioner Ramzi Jabbour, said the bust would hinder the drug trade in Australia.

“We’ve been exceedingly successful - on this occasion we’ve taken the legs out from underneath them, but we’re not resting on their laurels.

“With respect to the price of the commodity [cocaine] on our streets, this is an indication that it is readily available, but efforts like this will certainly make an impact.”

Assistant Commissioner Jabbour said the bust had potentially stopped more than 750,000 deals taking place on Australian streets.

Project Cringle has resulted in 10 arrests and the seizure of almost two tonnes of cocaine destined for Australia from five vessels.