Drug users who use medically supervised injecting rooms are far less likely than other addicts to commit a crime, inject in public, overdose, share needles or have abscesses, a study shows.

The results were garnered through the first control study of injecting rooms, which compared two groups of drug users who either did or didn't use the facilities in the French cities of Paris and Strasbourg.

The findings supported injecting rooms as public health "no-brainers", Harm Reduction International executive director Naomi Burke-Shyne said.

"The irony of the profound failure of the war on drugs is that it has actually driven the illicit production of more and more substances and has led to more toxic drug supply," Ms Burke-Shyne said.

"In order to save lives, we must offer overdose prevention and supervised spaces for people injecting drugs, together with pill testing, to understand the potency, adulteration or toxicity of a substance.

"(We must also offer) medically supervised injection rooms, the medicine naloxone to reverse overdoses, and drug checking technology work."

The study's results were on Tuesday unveiled at the Melbourne-based Harm Reduction International Conference, as the Victorian government considers whether to approve a second medically supervised injecting room in the city's CBD.

The government in March announced a facility at North Richmond in inner Melbourne would continue to operate indefinitely after a controversial trial that divided locals.

The Andrews government opened the supervised injecting room at North Richmond in June 2018 as part of a two-year trial.

As of March, there were 50 heroin-related deaths in the local council area in the 42 months since the facility opened, down from 68 deaths during the preceding 42 months.

Ms Burke-Shyne said more medically supervised injecting rooms in Australia and abroad were inevitable.

"No one should die of an overdose," she said.

Medically supervised injecting facilities - also called drug consumption rooms - are used officially in 16 countries, including Switzerland, the Netherlands, Germany, Denmark, Spain, Canada and Australia.

Results from another New York-based control study are expected in the first half of this year.

A separate US-based study, also presented at the Melbourne conference, showed people were increasingly using fentanyl and gaining tolerance to the drug, despite having a preference for heroin.

The Harm Reduction International Conference in Melbourne runs until Wednesday.

More than 1000 delegates have come together to share the latest research on best practice in drug policy, harm reduction and human rights.