Links between "violent" Mexican cartels and bikie gangs are being probed after authorities intercepted a billion-dollar ice haul bound for Australia.
The seizure of 1.7 tonnes of the drug in California on January 9 was also the biggest ever domestic seizure of methylamphetamine in the US.
"This is the largest seizure of ice bound for Australia ever. This is the largest seizure ever located in the USA," Australian Federal Police Assistant Commissioner Bruce Hill told reporters in Melbourne on Friday.
Authorities believe the Mexican cartel has links to Australian based outlaw bikie gangs but would not give any more detail.
"We now believe Mexican cartels are actively targeting Australia, they have been sending smaller amounts of ice over the years but this is now flagging the intent that Australia is now being targeted," Mr Hill said.
"This cartel is among one of the most powerful and violent drug trafficking syndicates in the world."
The investigation began after police intercepted a vehicle in northern Victoria last year, and found 25kg of ice. The suspect was linked to organised crime with outlaw motorcycle gangs.
Three people fronted court on Friday on charges including attempted drug importation and possession with the trio remanded for their next appearance on June 17.
A fourth person is also facing drugs charges.
Two men from Sydney will also be extradited to Melbourne to face court.
Investigations are ongoing.
Australian Associated Press