Australian police have seized millions of dollars worth of MDMA, commonly known as ecstasy, from a cargo ship, the Australian Federal Police (AFP) said on Friday.
About 120 kilograms of MDMA, worth about $6.6 million Australian ($4.3 million US), was found inside six vans aboard the ship docked in Western Australia in February, police said.
The ship had come from Europe, AFP acting commander Peter Hatch said.
Police were working with international partners to find those responsible.
"This importation plot would have required a lot of planning and the involvement of a number of people," Hatch said.
"The AFP and its partners in Australia and overseas are working tirelessly to prevent all illicit drugs from reaching our communities, where they cause more crime and misery."
Australian Border Force acting commander James Payne said it was "another demonstration of an audacious attempt to conceal the importation of a dangerous drug" that had been thwarted by authorities.
"We are working together with our law enforcement partners to ensure the border remains a hostile environment for criminal syndicates attempting to use our ports for their illicit schemes."