Police have thwarted an attempt to get a 312kg haul of liquid methamphetamine, disguised as vegetable oil, into Australians' hands.
The mammoth consignment was first detected at Los Angeles International Airport in July, when US Homeland Security special agents and border protection officers found the drugs labelled as "'vegetable fluid oil" hidden inside two black drums.
The discovery set a mission dubbed Operation Tallow into motion, with Australian police working with US authorities to trace the drugs as they made their way to Victoria.
The consignment was held in storage for a fortnight when it landed on Australian shores.
On September 5, it was delivered to a vacant rural property near Tooborac about 100km north of Melbourne, the Australian Federal Police said.
When nobody came to pick up the haul, investigators raided properties at Melbourne and Brisbane and interviewed a number of people.
However, nobody has been charged over the consignment.
Officers seized the drugs and federal police had no intelligence to determine whether the haul was intended to be moved to another location.
Investigators on Thursday appealed for anyone with information about the consignment to come forward.
"We are certain there are people in Australia who know something about this importation, or may have seen suspicious activity in the vicinity of Tooborac during the past few weeks," AFP Detective Superintendent Kristie Cressy said.
US Homeland Security would continue to work with the AFP to track down who was responsible for the smuggled methamphetamine, regional attaché Ernest Verina said.
"Criminal organisations that display such a wilful disregard to our community's safety to sell this deadly poison, must be held fully accountable," he said.
Investigators will test the drugs further to determine their purity.