Toronto police say they have made a number of arrests at a Toronto condominium where residents complained to CBC News that an illegal massage parlour was operating.

Residents at 4091 Sheppard Avenue East complained to CBC News last month that an apartment in their building was being used for sex trade work for the past 10 years. They said their complaints were ignored.

In just a matter of weeks police have arrested six people at the condo and seized $20,000 in cash from one apartment.

Staff-Sgt. Dave Rydzik says police are patrolling the area more often.

"Sometimes we use undercover officers that will obviously pose as customers and once they're invited in they can conduct their investigation," said Rydzik.

Police forces across the GTA say they're seeing more and more illegal massage parlours popping up in residential buildings. Finding them and shutting them down is difficult, according to police.

Horst Kroll, a longtime resident of the condominium says he's received lots of compliments for leading the campaign to get rid of the massage parlours.

He says his neighbours say, "'You've done a really good job.' I have a lot of people helping me right now."

But Kroll, 74, says the management of his condo still hasn't taken action.

However, in an e-mail to CBC News a spokesperson for the building management says they are taking the situation very seriously and are considering making amendments to their condo rules.

Rydzik says there are hundreds of similar massage parlours across the city but police need proof and warrants before they can lay a charge.