A trio of safe injection sites is now open in Montreal.

Two of the locations have operated needle exchange programs for drug users for years, but as of Monday both Cactus and Spectre du Rue are also locations where people can inject drugs while supervised by medical personnel.

A third group, called L'Anonyme, is operating a truck that will move around the downtown core of the city of Montreal.

Although many groups, including parents of children attending a nearby school, oppose the safe injection sites, the president of Cactus said this will make the neighbourhood safer for all.

"When you see what is going on in Vancouver and in British Columbia actually, just for the month of May they already had 27 people die by overdose. So the crisis is not yet in Montreal but we have to be prepared," said Louis Letellier de St-Just.

The creation of safe injection sites comes as the result of a 2011 ruling by the Supreme Court of Canada known as Canada vs. PHS Community Services Society.

In 2003 the Vancouver Coastal health board received special federal permission to operate a safe injection site in the Downtown Eastside, one of the poorest neighbourhoods in Canada.

That exemption to federal law was renewed year-after-year until 2008, when the Harper government refused to do so.

The group operating the injection site took the government to court and won, with the Supreme Court ruling the government's arguments were inadequate.

Since then, after years of lobbying, groups in Montreal have been granted the right to operate the safe injection sites.

Letellier de St-Just said the sites will save lives.

"We know that we have 70 people who are dying by overdoses every year. These are actual data, so these new services will make sure that these people will come to a safe place," he said.

Like the existing needle exchange programs, drug users who visit Cactus, L'Anonyme or Spectre du Rue will be informed about their options, and be given help in trying to kick their dangerous habits.

"They will have access to medical services, to social services, and their dignity will be back as well," said Letellier de St-Just.

He estimated that 4,000 people will be using the safe injection sites each year, with each location being visited by about 100 drug users each day.

A fourth location will open in Montreal in several months.