A police officer can be seen inside the compassion club on St. Laurent Boulevard in Montreal. (CBC)

Police have arrested 35 people in raids on five cannabis clubs in Montreal and Quebec City that sell marijuana to people who need it for medicinal purposes.

Montreal police said the administrators of the compassion clubs, as they are known, and those involved in selling marijuana have been arrested. The former leader of the Marijuana Party, Marc-Boris St-Maurice, was among those arrested Thursday.

Some clients of the clubs were receiving marijuana without the proper federal authorization, police said. Selling to such people constitutes illegal drug trafficking, said Montreal police Cmdr. Antonio Iannantuoni.

"People who are sick, who have authorization from Health Canada, are not the ones targeted by our investigation," he said.

In May, an investigation by the French-language service of the CBC raised questions about the ease with which it is possible to obtain marijuana from compassion clubs.

After explaining that he needed the drug to deal with migraine headaches, a reporter with the Radio-Canada program Enquête was told he would have to provide a doctor's note or a sworn declaration from a commissioner of oaths.

A staff member suggested the reporter say he was suffering from chronic pain and directed him to a building down the street.

A commissioner of oaths was waiting there to sign a declaration for a $10 fee.

The current investigation began in early 2010, said Iannatuoni, after police received several complaints about the clubs.

'They just walked in out of nowhere'

Police began serving warrants shortly after noon on Thursday.

They seized nearly 60 kilograms of marijuana, a small amount of hashish and $10,000 in cash. They expect to lay charges of drug trafficking and conspiracy.

"They just walked in out of nowhere, showed us the paper and said, 'There's the warrant'," said Maria Koklas, a volunteer at the Culture 420 compassion club in Lachine.

"There's about 15 to 20 cops in here walking around inside the dispensary taking all of our … [members'] IDs, asking them for all their personal information, asking them for their criminal records and letting them know if they don't have criminal records, they will be free to go."

In addition to the raid on the Lachine club, Montreal police carried out operations at three clubs in the Plateau Mont-Royal neighbourhood.

In 2000, Montreal police raided a compassion club on Papineau Avenue. But when the case went to trial, a judge ruled it was unconstitutional to deny people an opportunity to get marijuana after saying they could use the drug for medical reasons.

Details on the raid in Quebec City weren't available.