Unless the federal government quickly updates its icebreaker fleet it could face considerable economic problems, including the port of Montreal losing container service to competitors in the U.S., according to internal documents viewed by Radio-Canada.

The documents prepared for the federal cabinet warn that Ottawa could pay a high price for not replacing the coast guard's aging icebreaking vessels — and that Quebec could bear the brunt of the cost.

The internal analysis says the ports of Montreal and Quebec City are at risk of being partly cut off in the winter months, with thousands of direct and indirect jobs at stake.

The document also warns that Quebec's maritime strategy, a flagship project for Premier Philippe Couillard, is on the line if Ottawa doesn't replace its aging icebreakers. The $9-billion plan aims to create 30,000 jobs by 2030.

Canada's newest icebreaking vessel is 30 years old. Its two heavy icebreakers were launched in 1968 and 1983 respectively.

Heavy ice and a lack of reliable coast guard icebreakers have already caused significant delays in the Gulf of St. Lawrence and estuary.

The document warns that in a competitive global marketplace these delays are "unacceptable" and maritime transport remains "the backbone" of trade.

Independent report flags similar issues 

John Holliday, president of Montreal's Lantic Sugar Ltd., which processes about 500,000 tonnes of raw sugar annually, said he depends on ships arriving from Brazil.

"If this corridor is unreliable and the supply disrupted, it could have a catastrophic impact on our plant," he said in an interview in French with Radio-Canada, CBC's French-language service.

Holliday said the government needs to understand the risks and the responsibility to invest.

A 2016 independent report for Transport Canada also flagged issues with the country's coast guard fleet, saying it is understaffed, desperately in need of new ships and without political support.

It warned that coast guard icebreaking services in the Arctic are decreasing, while vessel traffic in the region is increasing. It blames the number of breakdowns on underfunding of maintenance by the previous Conservative government, and a general neglect by politicians in Ottawa.

Vancouver-based Seaspan Shipyards has been tapped to build replacement vessels for the coast guard, but work on a heavy icebreaker is not expected to get underway until 2020-21.

With files from Radio-Canada's Marc Godbout