By Paul Vieira

OTTAWA — Canada will provide billions of dollars to help upgrade infrastructure and clear congestion at the country's biggest port in Vancouver, British Columbia, Prime Minister Mark Carney said Thursday.

The money is meant to address warnings that constraints at Canada's ports posed a sizable hurdle in efforts to reduce dependence on crossborder trade with the U.S. to drive growth.

Carney said his government would provide the equivalent of $7 billion to expand capacity at the Vancouver Fraser Port Authority. At a press conference in the Pacific Coast city, he said the infrastructure upgrades would help unlock over $70 billion in new trade capacity and add over $2 billion in output.

Carney, and analysts at the Bank of Canada, had warned this year that the country had fallen behind on upgrading the infrastructure at its marine ports. The central bank warned strains on port capacity threatened to thwart Carney's bid to diversify trade to new non-U.S. markets.

The port of Vancouver handles roughly $700 million in commerce each day, and more cargo than the next five largest Canadian ports combined.

The port's success "is now straining capacity and bottlenecks are worsening," Carney said. "Ships wait to load their cargo. It takes too long to get imported goods to Canadians. That slows our trade, loses new business to the U.S., increases prices here at home, and holds our economy back."

Write to Paul Vieira at paul.vieira@wsj.com