Crystal meth drug methylamphetamine worth €803 million has been seized in Australia's largest haul of the substance in its liquid form.

Four Hong Kong passport holders were arrested in Sydney last month over the import from China of 190 gallons of the drug hidden in boxes of silicon bra inserts and art supplies, police said.

The liquid could have made about 1,100lbs of high-grade crystal meth, commonly known in Australia as ice, Australian Federal Police commander Chris Sheehan said.

Officials also seized 4.4lbs of the crystallised form of the drug.

Justice minister Michael Keenan said the operation used information gathered through new co-operation between Australian Federal Police and China's National Narcotics Control Commission.

The Australian and Chinese agencies established a joint task force in November to investigate criminal syndicates trafficking methamphetamine.

"This largest seizure of liquid methylamphetamine to date is the result of organised criminals targeting the lucrative Australian ice market from offshore," Mr Keenan said.

The four will appear in a Sydney court next month charged with importing and manufacturing commercial quantities of illegal drugs. Each faces a potential life sentence if convicted.

Mr Keenan said the seizure was one the largest hauls of illicit drugs in Australian history.