The Canadian submarine that sent a distress signal from the Atlantic 180km northwest of Ireland is on the surface and the situation is under control, according to the British Navy.

A spokesperson for the British navy base at Faslane on the Clyde says that a fire broke out board the HMCS Chicoutimi following an electrical fault, causing heavy smoke throughout the vessel.

Three people are reported to have suffered from smoke inhalation, but their injuries are not said to be life-threatening.

A helicopter went to the scene from the Royal Air Force's Prestwick base in Scotland, and a Nimrod long-range sea patrol plane was also dispatched to the non-nuclear submarine, a British navy spokesman earlier confirmed.

It is understood that there are about 50 personnel on board the submarine, which originally belonged to the British Navy but was sold in a refitted form to Canada in 2000.

The Department of the Marine earlier said it had been asked by British authorities to prepare a refuelling facility for possible use in the recovery operation.