Some Canadian shipbuilders are concerned a German design could be the leading contender to replace the navy's aging sea support ships.

Replenishment ships, like the Preserver and the Protecteur, help the Canadian navy stay at sea for long periods of time, but at 40 years old, they'll soon need replacements.

Sources have told the CBC that a German-designed ship called the Berlin class could win the $3-billion contract.

Since the Second World War, Canada has designed and built its own warships. However, in recent years, the German industry has lobbied the Canadian government to supply designs for frigates, destroyers and new submarines.

Peter Cairns, president of the Shipbuilding Association of Canada, said buying an existing foreign design means the Canadian industry loses out.

"You can get vessels off the shelf cheaper," he said.

"[There's] no Canadian input with the exception of the odd piece of pipe."

Cairns said he's concerned the sea support ship contract could signal the demise of a decades-old Canadian design industry.

"This Berlin class is going to come with German radars, German engines, German this, German that, and German the rest of it."

The federal government has promised to build new arctic patrol vessels and navy combat ships in Halifax over the next 30 years.