Police raided 19 homes across Adelaide and found sophisticated hydroponic operations in 12 of the properties.

Officers seized 642 plants, 61kg of dried cannabis, $29,000 cash and one vehicle.

It's suspected the marijuana was to be sold across the country and police have evidence that some money made from the trafficking operation was sent to European countries.

Three men, aged 37, 39 and 40, were arrested and charged with serious drug offences including the cultivation of a commercial quantity of cannabis and trafficking.

Detective Superintendent Stephen Taylor said the seizures and arrests should act as a deterrent to those involved in organised crime rings.

"While they might be enjoying the benefits of their criminal enterprise with their high-end vehicles and luxury homes, there's a fair chance they will be caught," he said.

"They are rolling the dice with their own freedom and at some stage, their number will come up and they'll have plenty of time to reflect on whether it was all worth it."

Supt Taylor said the coronavirus pandemic and its travel restrictions had impacted on the operation of some drug networks.

But he said there was evidence to suggest that drugs were still crossing state borders, including in trucks and through the postal service.

The homes raided this week were all set up simply to grow drugs, with no evidence anyone was living there.

All the properties had their electricity meters bypassed in a bid to avoid detection.

Australian Associated Press