Ontario is joining five other provinces in a class-action lawsuit against dozens of opioid manufacturers.

The province passed legislation late Wednesday allowing it to join the British Columbia-led suit, which alleges that drug manufacturers falsely marketed opioids as less addictive than other pain drugs.

The suit seeks to recover costs from manufacturers and distributors dating back to 1996, when the pain drug OxyContin was introduced in the Canadian market.

Ontario has said it would invest any potential awards from the litigation into front-line mental health and addiction services.

New Brunswick, Newfoundland and Labrador, Saskatchewan and Alberta have already announced their support for the lawsuit.

The latest numbers from a national advisory committee studying the opioid crisis show close to 14,000 Canadians have been killed by the drugs over the last four years.