Up to 300 kilograms of pure pseudoephedrine has been discovered hidden in a consignment of washing powder shipped to Melbourne.
A 40 foot container allegedly held 160 boxes of pseudoephedrine hidden among more than 900 boxes of washing powder.
Five men have been charged with drug importation offences after police seized the drug precursor, the Australian Federal Police said on Monday.
The accused men appeared in court on the weekend.
The pseudoephedrine is believed to have come from Vietnam. It arrived into Melbourne in mid-December.
Pseudoephedrine is an ingredient in methamphetamine.
Authorities say the seized precursor could have produced methamphetamine valued at $42 million wholesale. It could have 1.5 million hits worth more than $200 million on the street.
The bust came after a joint operation by the AFP, Victoria Police, Australian Border Force and the Australian Criminal Intelligence Commission.