OTTAWA -- A pair of think-tanks say the Harper government should either announce plans to scrap its glitch-plagued submarine fleet -- or begin the process of replacing them before any more tax dollars are wasted.

The Canadian Centre for Policy Alternatives and the Rideau Institute say the Victoria-class submarines, purchased second-hand from Britain in the late 1990s, are within a decade of ending their service life, and have never lived up to expectations.

A report written by defence and law academic Michael Byers and researcher Stewart Webb asks whether Canada, bordered on three sides by oceans, even needs submarines.

"I don't see a strong case for Canada to require submarines," Byers said Tuesday during the report's release on Parliament Hill.

"We remain open-minded. If the government can come back with a convincing case, we will look at it."

All of the public arguments made for sticking with the troubled program, including covert operations against drug-smuggling ships, "don't hold water," Byers said.

The stealth coastal surveillance aspects of subs is rapidly being overtaken by unmanned aerial vehicle technology, Byers added.

The national shipbuilding strategy is silent on whether the Conservative government intends to replace the current submarine fleet, something Byers says means the decision has either been made, or the file is being horribly mismanaged.

Almost 15 years after it was acquired by the Chretien government, HMCS Victoria fired its first torpedo last year and was declared fully operational by the navy. The three boats, including HMCS Chicoutimi which suffered severe damage in a 2004 electrical fire, are in various states of overhaul, upgrade and limited operations.

"The question needs to be posed: Are we throwing good money after bad? Is there a strong case for maintaining a submarine capability, and if not, isn't it time to wake up?" he said.

The former Liberal government originally set aside $895 million for the purchase and activation of the boats, but the Defence Department has subsequently spent almost double the amount. In addition, the Harper government in 2008 approved a 15-year, $1.5-billion support and refit contract for the submarines.

The outgoing commander of the navy, Vice-Admiral Paul Maddison, told a Senate committee some months ago that the boats, once all are declared fully operational, would remain service until at least 2030.

At the same time, internal briefing records obtained by The Canadian Press last year show defence planners have already turned their attention toward what might replace the current fleet.

Officials made the case to the former chief of defence staff that investing in submarines was prudent because "in the event of global tensions these relatively cheap assets will counter projection of power and hinder freedom of movement and action."

The briefing suggested Canada's next generation of submarines should be sophisticated enough to launch unmanned underwater surveillance robots and fire missiles at shore targets.