Ottawa police made 117 arrests in prostitution-related sweeps last year, but in a dramatic shift from just four years ago, all of the people arrested were "johns", or men police say were attempting to pay to have sex.

Two years ago, former Chief Vern White came out publicly to warn prostitutes about a dangerous sexual predator. Insp. Chris Rheaume with the Ottawa police said it marked the beginning of a new approach for the police force.

"We stopped targetting prostitutes and we went after the johns," said Rheaume.

Insp. Chris Rheaume

Ottawa police Insp. Chris Rheaume said he believes the shift in policing has made the streets safer for women. (CBC)

In 2009 police made 191 arrests — 135 women and 56 men. Since then the number of women arrested has steadily declined. In 10 "john sweeps" this year, no prostitutes were arrested, said Rheaume.

He said when police switched their focus, they were surprised with what they found.

"Its not just boom, arrest the guy, but boom, arrest the guy, get a search and uncover things," said Rheaume. "We've had males where they had drugs that would knock out women, we've had males that had bondage things. So they had other plans in mind when going out looking for those females."

He said the arrests have led to a number of more serious charges, including murder charges involving at least two prostitutes.

The changes in police tactics were announced two years ago at the Minwashin lodge, which runs an outreach program for prostitutes called STORM that meets with up to two dozen women each night.

Mary Daoust, a case manager and sexual abuse counsellor at the lodge, said many sex-trade workers had trust issues with police, but said the shift has been welcomed.

"When they see arrests they know that police doing their job to keep them safe," she said.

"If it decreases the risks for women on the street, we'd support whatever that looks like," said Daoust.

Groups advocating for sex-trade workers have traditionally opposed sweeps of any kind, for fear they would drive prostitution further underground and leads to greater risks for the women.

But Rheaume said he hopes the change in policing is appreciated and said police are now making greater efforts to talk to sex-trade workers through outreach workers.

"There's open lines of communication, which we didn't have before," he said.