Canada’s parliament has passed a bill that that will cover the full cost of contraception and diabetes drugs for Canadians.

The Liberal government said it is the initial phase of a plan that would expand to become a publicly funded national pharmacare programme.

The government estimates one in five Canadians struggle to pay for prescription drugs.

The federal government still has to negotiate individual funding commitments with Canada’s provinces and territories.

A report from parliament’s budget watchdog estimates this bill will increase federal spending by C$1.9bn ($1.3bn; £1bn) over the next five years.

Canadians currently pay for prescription drugs through a mix of private, public and out-of-pocket plans.

The programme will cover 100% of the cost of diabetes and contraception medication for those who do not have drug plan coverage, and out-of-pocket costs for those who do.

The federal government estimates that nine million Canadian women of reproductive age will have access to common types of contraception under the plan.

Birth-control pills and IUDs can cost between C$100 and C$300 a year.

The Society of Obstetricians and Gynaecologists of Canada hailed the ball as a “historic achievement”.

“Women across the country will be able to make choices about contraception based on what’s best for their lives, not their wallets,” it said.

In addition, some 3.7 million Canadians have been diagnosed with diabetes.

Diabetes drugs covered include insulin – for people with type 1 and type 2 diabetes, which can cost between C$900 and C$1,700 a year – and Metformin, which helps lower blood sugar levels for people with type 2 diabetes.

Speaking to reporters on Thursday from the Association of Southeast Asian Nations Summit, Prime Minister Justin Trudeau called the bill’s passage “real progress” and urged provinces to quickly move forward with signing agreements.

The federal health minister has said he hopes that some provinces will have the plan in place by the end of this year, with all on board by next spring.

British Columbia has already signed a memorandum of understand agreement with Ottawa.

But two provinces – Alberta and Quebec – have indicated they may opt-out of the programme, accusing Ottawa of interfering in provincial matters.

Opposition Conservative leader Pierre Poilievre, whose party is ahead in national polls by a wide margin, does not support the legislation.

Some critics of the bill have also warned it lacks clarity.

In a statement, the Canadian Chamber of Commerce said the government only recently confirmed pharmacare would be a universal, single-payer system.

“They chose a costly model that will deteriorate rather than improve access to prescription drugs, violate provincial jurisdiction, and further burden Canadian taxpayers,” the business group said.

The pharmacare bill stems from a deal between the New Democratic Party (NDP) and the minority Liberals.

The left-wing party promised to prop up the Liberals on the condition that the government launch the drug programme, along with a handful of other priorities.

The NDP pulled out of that deal in early September, making a snap general election before the one currently scheduled for October 2025 more likely.

Canadians spent an estimated C$41bn on prescription drugs last year, with C$15bn covered by private plans and just over C$8bn out-of-pocket, according to the Canadian Institute for Health Information.