Policing practices in Vancouver's Downtown Eastside are creating barriers for people wanting to access overdose prevention sites, according to a new study by the B.C. Centre on Substance Use and the University of British Columbia.

The study also found police presence in the area increased the risk of overdose for drug users.

Researchers began collecting data in December 2016 and did more than 200 hours of fieldwork in areas near overdose prevention sites, including interviews with 72 people who use drugs.

"Intensifying policing presences around overdose prevention sites means people aren't able to access [the sites] and then they're pushed into unsafe injecting environments and especially are much more likely to inject alone," said lead author Ryan McNeil.

McNeil said tactics used by the Vancouver Police Department include focusing on areas where drug use and sales are common. The study found having fewer car and foot patrols in the area and reducing police presence near overdose prevention sites would help break some of the barriers.

"We need to move toward more humane approaches to allow us to more fully respond to the overdose crisis and that means removing barriers to life-saving services," McNeil said.

The study also suggests removing court-ordered area restrictions — known as red zoning — which prevent a person from going back to the area where they were previously arrested. Such restrictions create another obstacle for those looking to access overdose prevention sites, McNeil explains.

The province declared the overdose crisis a public health emergency more than three years ago. (Maggie MacPherson/CBC)

Some of the people interviewed also reported they have hesitated to call an ambulance for fear of police showing up, according to the study.

"We're in a public health emergency and one of our primary responses continues to be the criminalization of people who use drugs," he said. "We do this for nothing else, there's no other health issue that is directly criminalized in the way that drug use is."

The province declared the overdose crisis a public health emergency more than three years ago.

Vancouver police say staff have not had a chance to review the report and will provide comment after they've had an opportunity to read it.