The operation involved four separate hauls in 2023 after attempts by importers to hide the drug in bottles of canola oil destined for Victoria and NSW from Canada.
The drugs weighed a combined six tonnes, the equivalent of about 19 million street deals, according to investigators.
It is one of the largest drug seizures in Australian history.
In January, $720 million worth of liquid methamphetamine was smuggled from Canada to Australia inside 180 bottles of canola oil.
Detector dogs helped identify the drugs inside shipping containers before the methamphetamine was secretly substituted with a harmless substance.
Authorities kept watch as two men moved the bottles to storage locations in Melbourne before the material was distributed across Victoria.
In May and June, Canadian authorities seized two further shipments of liquid methamphetamine hidden in canola oil bottles with a combined street value of almost $800 million.
One of the hauls involved 2900 litres of the drug from the Vancouver area, the largest methamphetamine seizure by Canadian border authorities.
On Wednesday, authorities executed search warrants at a home and a storage unit in Melbourne, finding a large quantity of drugs, cash and firearms.
Two men from Melbourne, aged 32 and 38, were charged over the January import and were set to face court on Thursday.
The 38-year-old is accused of being a conduit for an organised crime network in Canada, while the 32-year-old allegedly used his position in a logistics business to transport the goods once they arrived in Australia.
If found guilty they both face a maximum penalty of life behind bars.
A 28-year-old Sunshine North man, a 26-year-old US national and a St Albans man, 19, were charged with attempting to possess a commercial quantity of unlawfully imported border controlled drugs following the searches in Melbourne.
Police allegedly uncovered a clandestine laboratory to manufacture drugs and the trio could face further charges.
Meanwhile, a 51-year-old from Melbourne was charged with possession and trafficking of a marketable quantity of border controlled drugs, dealing with proceeds of crime and other offences.
Police expect further arrests will be made.
The investigation involved the Five Eyes partnership, an intelligence alliance involving Australia, the United States, United Kingdom, New Zealand and Canada.
Australian Federal Police Assistant Commissioner Hilda Sirec said transnational organised crime groups posed a significant threat to national security.
"They tend to corrupt officials to get their drugs into the country and they collude with other criminal groups like outlaw motorcycle gangs and other local syndicates, which are violent and have been responsible for some of the deadly drug wars playing out," she told reporters.
Victoria Police Assistant Commissioner Bob Hill said Australians had an "insatiable appetite" for illicit drugs, creating a lucrative market for organised crime.
"Our use of methylamphetamine in this country, per capita, is matched by no other nation in the world," he said.
In January, six people were charged in New Zealand over a 713kg haul of crystal methamphetamine that was suspected of being sourced from the same organised crime group.
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