Many Western Australians would be horrified to learn they have been buying fruit and vegetables produced by exploited people, WA Police Minister Liza Harvey says.

Her comments follow raids on market gardens and houses in Perth's north yesterday which saw guns, cash and computers seized, and 180 foreign nationals questioned by police.

"Over time as this unfolds I think there will be some shocking revelations," Ms Harvey said.

"I think there will be out of this investigation a lot of horrified Western Australians and Australians who would have had no idea that they have been eating fruit and vegetables and buying product from a company that has exploited so many people."

An area of Carabooda in Perth's northern suburbs was shut down yesterday after Tactical Response Group officers descended on a walled community containing about six houses.

Women and children are understood to be among the dozens questioned, but police say the main focus of the raids is not on them, but on a money laundering operation.

The operation, which involved 550 law enforcement officers and 12 months of surveillance and investigation, has been described as the biggest of its kind in Western Australian history.

No formal charges have yet been laid, but Ms Harvey today said workers had been forced into accepting unreasonable work conditions.

"They have been shanghaied into working at low rates and in conditions that other Australian workers would never tolerate," she said.

"Taking advantage of people who are desperate for employment and desperate for a new life, they are the lowest of the low."

She praised the work of the officers involved.

"It's a really big bust, it's a very big organised crime ring and I'm very proud of our officers who have been involved in this," she said.

"It's an ongoing police investigation and they're still uncovering the depth and the spread and the reach of this crime gang."

"On the range of activities that have been uncovered, there will be a number of very serious charges that will come out of this investigation."