Two trusted customs brokers have been charged over the country’s largest ever seizure of the drug ice, with federal police alleging the pair was "middle to high up" in the international operation.

The record methamphetamine haul, worth more than $1 billion, was found hidden inside speakers shipped to Melbourne in April.

On Wednesday, more than six months after the drugs were seized, federal police descended on homes and cars in the Melbourne suburbs of Darley, Sunshine West, Brooklyn, Elwood and Murrumbeena and arrested two men and a woman.

Business colleagues Rachel Cachia and Donovan Rodrigues, both 37, and IT worker Stephen Mizzi, 38, have been charged, with police alleging they imported more than 1.6 tonnes of illicit drugs.