The Ontario government will announce Monday that it intends to join British Columbia's proposed class action lawsuit against dozens of opioid manufacturers.

A spokeswoman for Health Minister Christine Elliott says officials will release more details about Ontario's plans to join the suit when the Progressive Conservative government introduces legislation on Monday.

B.C. filed the proposed class action against dozens of pharmaceutical companies last year in a bid to recoup the health-care costs associated with opioid addiction.

The untested suit alleges the companies falsely marketed opioids as less addictive than other pain drugs and helped trigger an overdose crisis that has killed thousands since OxyContin was introduced to the Canadian market in 1996.

It names the maker of OxyContin — Purdue Pharma Inc. — as well as other major drug manufacturers, and also targets pharmacies, including Shoppers Drug Mart Corp. and its owner Loblaw Companies Ltd., claiming they should have known the quantities of opioids they were distributing exceeded any legitimate market.

Ontario Attorney General Caroline Mulroney and Elliott's parliamentary assistant are expected to give more details when the legislation is announced.

In a separate Ontario case earlier this month, lawyers representing patients who became addicted to opioids filed a statement of claim seeking more than $1.1 billion in various damages from nearly two dozen companies.

That suit alleges the companies were negligent in how they researched, developed and marketed opioids starting in the 1990s.