A Keilor Downs pair have been arrested in connection to a record seizure of methylamphetamine, valued at more than $1 billion.

A 31-year-old man and 29-year-old female were arrested in Keilor Downs after warrants were executed across Melbourne’s north-west on February 7 and 8.

It comes after a lengthy investigation between US and Australian border forces, which uncovered a large quantity of drugs bound for Australia from California in two large containers purporting to contain audio equipment.

The drugs were seized in California by US authorities on January 9 before they could reach Australian shores.

The seizure included 1.73 tonnes of methylamphetamine, estimated to be worth more than $1.29 billion and equal to more than 17 million drug deals.

Police also seized 25 kilograms of cocaine, worth an estimated $9.5 million, and 5 kilograms of heroin, worth an estimated $2.6 million.

The previous record seizure of methylamphetamine bound for Australia was 1.3 tonnes, seized in Western Australia in 2017.

Police executed warrants in Woodstock, Pakenham, Derrimut, Campbellfield, Keilor Downs and Epping, resulting in the arrest of two U.S. nationals and the Keilor Downs pair.

All four are expected to appear in the Melbourne Magistrates Court today to face a range of drug importation charges.

Australian Federal Police Assistant Commissioner Organised Crime, Bruce Hill, said the joint task force investigation demonstrated the effectiveness of Australian and international authorities working together to stamp out illicit drug importations.

“This is the biggest ever seizure of methylamphetamine – more than 1.7 tonnes – stopped before it had a chance to reach Australian streets. By stopping this, we have ensured criminals will not profit from the immense pain these drugs would have caused our community,” Assistant Commissioner Hill said.

“I wish to thank our U.S. counterparts for their expert involvement in this investigation and strong support of our efforts to keep these drugs off Australian shores.”