MONTREAL — The long-planned extension of a Montreal subway line will open in 2029 and cost some $6.4 billion, government officials said Friday.

It is the fifth time in the last 33 years that politicians have announced an extension of the metro's blue line. On Friday, Quebec cabinet minister Chantal Rouleau promised that this time, the infrastructure will be delivered.

"Citizens have waited too long," Rouleau, the province's minister responsible for Montreal, said. She was joined at a news conference by federal Heritage Minister Pablo Rodriguez and Montreal Mayor Valérie Plante.

Four years ago, then-premier Philippe Couillard was accompanied by Plante, Rodriguez and Prime Minister Justin Trudeau to announce that five stations serving the city's east end would be complete by 2026 at a cost of $3.9 billion. Like Friday's announcement, that event came in a provincial election year.

An extension was previously announced by Pauline Marois's government in 2013, and by former premier Jean Charest four years before that.

To show the government is serious, Rouleau said the province had given the go-ahead for the city's transit corporation to begin looking for qualified companies to carry out the tunnelling.

Éric Alan Caldwell, a city councillor and chair of the transit corporation's board of directors, also assured skeptics that the work will start soon. "The cheque is in the mail, now we're digging and starting," he said.

Excavation work is scheduled to begin in 2023 and construction is expected to last six years. The bulk of the funding comes from the province, with a $1.3-billion contribution from the federal government.

Rodriguez, Rouleau and Plante said the new cost estimates for the project account for inflation as well as possible supply chain delays.

The extension of the east-west blue line has been discussed, in various forms, since 1979, and no new subway stations have been built in Montreal since 1988. Plante said the extension would allow for further economic development of the city's east end, including the building of some 13,000 housing units.

This report by The Canadian Press was first published March 18, 2022.

Stéphane Blais, The Canadian Press

Note to readers: This is a corrected story. A previous version referred to Prime Minister Pierre Trudeau.