An exemption from Health Canada to grow medicinal marijuana is opening the door for criminals to hide illegal grow-ops, according to experts.

Darryl Plecas, a criminologist with B.C.'s University of the Fraser Valley, says police are finding more "sanctioned" grow operations across the province -- operations where the proprietor has legal permission from the government to cultivate marijuana for medicinal purposes.

"Health Canada has been wrestling with this problem," he said.

Plecas, who used to sit on Canada's medicinal marijuana advisory board, says the government agency does not have enough inspectors to monitor the situation.

"In effect, it amounts to virtually no enforcement," he said.

It is this lack of checks and balances surrounding medicinal grow-ops that is attracting organized crime.

"This new situation where people can grow legitimately and criminals will seize on that to say I will hide under that umbrella -- and if there are no inspections that will be the biggest reason why we have a problem," Plecas said.

Once someone has a permit to grow from Health Canada it is very difficult for police to investigate because of privacy concerns.

"That is something that can be abused by the criminal element to skirt detection," he said.

Plecas believes the problem could be solved if Health Canada stopped allowing people to grow pot at home.

"None of these hazards would be in place if we had marijuana for medical purposes grown in a commercial manner," he said.

But as it stands right now, some medicinal grow operations are becoming part of B.C.'s biggest illegal industry.

With a report from CTV British Columbia's Rob McKee