A key federal cabinet committee has given the go-ahead for a plan to construct six corvette-sized Arctic patrol vessels, the Canadian Press has learned.

The cabinet priorities and planning committee approved the program to build the 100-metre-long, 6,000-tonne warships within the last 10 days, according to defence and political sources.

The patrol vessels, which are almost as large as the navy's frigates, are a step down from the armed Arctic icebreakers that the Conservatives promised in the last election campaign and will likely not be in service before 2015.

Nevertheless, one political source said, "It'll be good for the military, good for Canadian industry and the Arctic is critical to our national interest."

Cabinet is said to have authorized a two-year definition phase in which the scope of the shipbuilding project will be laid out. Much of the cost of the new vessels — about $300 million apiece — is being put off until later years.

The vessels, which will be capable of smashing through fresh ice, are expected to be based on the Royal Norwegian Navy's Svalbard class design, a military source said. That particular type of vessel is armed with a 57-millimetre deck gun, missile-launching tubes and also has a helicopter pad.

The recommendation has gone forward to Prime Minister Stephen Harper for final approval.

'No final decision has been made'

"We are not commenting on cabinet discussions as they are confidential," said Isabelle Bouchard, a spokeswoman for Defence Minister Gordon O'Connor. "No final decision has been made. When we are ready we will make an announcement."

The Conservatives are deeply committed to protecting Canada's security and to asserting sovereignty in the North, including the country's internal Arctic waters, she said.

Cabinet is proposing to build the ships in Canada under a competitive process similar to the Defence Department's program to construct joint ships for the navy. Currently two consortiums, which involve foreign and domestic defence contractors, are vying to build three 28,000-tonne replenishment vessels.

The new ships were approved well before the Conservative government had a chance to consider a key policy paper, the Canada First Defence Strategy.

Rob Huebert, a professor of strategic studies at the University of Calgary, said the corvettes are a good step, but they cannot be the only solution for the Arctic.

"It makes sense only if the coast guard is getting its icebreaking fleet recapitalized," he said.

"If this is just a cheap buyout to allow the navy not to get icebreakers, and the coast guard does not get its very old icebreakers replenished, then we're going to be in a lot of hurt."

Last year, Fisheries Minister Loyola Hearn, who is responsible for the Coast Guard, was warned that the agency's fleet was experiencing severe "rust out" and needed to be replaced. As it stands, Coast Guard icebreakers are not due to begin being replaced until 2017.

Since the Tories were elected, there has been a fierce debate within National Defence over the party's campaign promise to build three armed icebreakers to protect Arctic sovereignty.

Icebreaking has traditionally been a role for the Canadian Coast Guard — one it has been loathe to give up — and many have argued that if new ice-cutting ships were to be built they should go to that agency, not the military.

In the end, the prohibitive $1 billion-per-vessel cost of armed icebreakers appears to have torpedoed the election promise. The navy was worried that such an ambitious program would seriously dent its well-laid plans to eventually replace its aging destroyers and frigates with a new single-class surface ship.

With global warming melting the northern ice pack, many experts have predicted the Northwest Passage will become a commercial waterway within the next few decades.