South-west police officers have uncovered seven crop houses in recent months and a cannabis drying operation.

The highly sophisticated operations have been located at Grassmere, Warrnambool, Portland, Hamilton and Horsham.

Operation Highrise has led to almost 2000 plants being ripped out with a potential street value of $4 million.

A number of Vietnamese nationals have been charged with the commercial cultivation of cannabis and are going through the criminal justice process.

Many of the properties have been bought to house the operations and police are looking at seizing them as proceeds of crime.

It's believed cheaper rent and house prices in the country compared to Melbourne is driving the industry into regional Victoria.

But there's a bigger statewide problem.

In a completely separate operation, Ballarat police found 16 crop houses in eight months leading up to October 2016 worth $8 million.

Each crop house involves electrical bypasses, transformers, lights and sophisticated watering and fertiliser systems.

At the Grassmere property last week hundreds of containers of expensive fertiliser were found.

It's suspected specialised crop growers are being employed by the Middle Eastern crime gangs to monitor and control the systems.

"It's highly specialised. You need a unique set of skills to run these operations. We are not just talking about growing a bit of grass," a police officer said.

South-west police are expecting to bust more crop house in coming weeks.

Officers are using unique investigating techniques to identify and locate the operations.

The commercial supply of cannabis is suspected to generate massive amounts of cash to fund both domestic and international crime.

Responses to questions put to Victoria Police media this week indicated the force lacks a coordinated approach to tackling the industry estimated to be worth hundreds of millions of dollars.

A Victoria Police media liaison spokeswoman said cannabis crop houses continued to be an area of concern.

"Police have cannabis disruption operations statewide and we continue to dedicate resources toward investigating and dealing with the cultivation of recreational drugs and crop houses," she said.

"Landlords and real estate agents should contact police if on inspection they notice:

It is understood south-west police are not relying on such information to locate cannabis crop houses.

Neighbours of the Grassmere property raided last week only reported seeing people at the house a couple of times in the past 18 months since it was bought.

They never saw a car.

A mechanic's shed was converted into an eight-room operation that housed 360 plants, most ready to harvest.

Generally establishing a crop house involves causing significant damage to the rental property or home that has been purchased.

Houses are re-walled, rooms re-lined to prevent any visibility and the interior is totally destroyed while lights and timers are installed along with watering and fertiliser systems.

Increasingly, police say traps are being set for investigating officers.

There is a propensity for offenders to set hazards for police attending - such as razor blades and fish hooks in the plants, live wires," one Ballarat senior officer previously said.

"There is increasing hazards set for investigative police - certainly safety remains a major concern for police."

Hundreds of lights are installed and the risk of fires is high.

"(Crop houses) are an extremely dangerous mix of live powers and watering systems. We have had multiple cannabis crop houses catch fire due to the supply pits overloading," the officer said.

"The vast majority (are run off) backyard electrical bypasses to avoid detection. One grow house will be utilizing sufficient energy to power eight normal houses."

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