A Chinese man and three Hong Kong nationals face life in prison after more than A$1bn ($700m; £500m) worth of methamphetamine was seized in Sydney.
Authorities said 720 litres (160 gallons) of liquid methamphetamine, much of it hidden inside gel bra inserts, was sent from Hong Kong.
Australian 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, foreign media reports.