Police in Sydney say they have seized methamphetamine with a street value of more than A$1bn ($700m; £500m), much of it hidden inside gel bra inserts.
A Chinese man and three Hong Kong nationals are facing life in prison after the seizure.
Authorities said the 720 litres (160 gallons) of liquid methamphetamine was sent from Hong Kong.
Justice Minister Michael Keenan said crime gangs had sought to profit from Australia's "lucrative ice market".
He said it was among the largest drug busts in the country's history.
"Ice" is a street name for methamphetamine in Australia.
The liquid seized in Sydney could have made 500kg (1,100 pounds) of high-grade crystal meth, Australian Federal Police (AFP) Commander Chris Sheehan said.
Mr Sheehan said the AFP worked closely with Chinese authorities as part of Taskforce Blaze, which cracks down on international methamphetamine trafficking syndicates.
Mr Keenan said: "3.6 million individual hits of ice were taken off our streets with a street value of $1.26 billion".
However, the A$1.26bn figure was questioned after Australian media noticed that police had changed the way they calculated the street value of the drug.
The AFP uses figures from the Australian Crime Commission (ACC) to calculate the value of illicit drugs. While it had previously used mid-point figures from the ACC, an upper-range figure was used to calculate the value of this haul, broadcaster ABC reported.