Oil from the wrecked tanker that broke up in the Atlantic two weeks ago has begun washing up on the northern French coast, where it is polluting beaches and killing wildlife.

An estimated 8,000 tonnes of oil has been drifting at sea since the ship broke up in stormy seas, despite desperate last-minute efforts to contain the leak.

Large stretches of the coast of the holiday island of Belle-Ile have already been polluted, and hundreds of slicks were visible off the island of Ile de Hoedic and the port of Quiberon.

Volunteers working in the region on Saturday collected at least 4,000 seabirds covered in oil, either dead or in great distress, according to the French Bird Protection League (LPO).

The thick viscous oil is particularly difficult to remove from the birds' plumage and more than 1,000 will be taken to refuges in the Netherlands for cleaning.

A total of 6,000 oil-soaked birds have now been found since the disaster on 12 December.

'Total devastation'

The president of the local wildlife centre on Ile d'Yeu said the scene there was one of "total devastation".

Jean-Yves Bannet warned locals not to attempt any clean-up themselves as it was "too dangerous", and said a proper effort would start on Monday.

Firefighters from Morbihan in Brittany have been sent to Belle-Ile to help clear up the pools of oil on the rocky coast and the sandy beach at Donnant.

French Environment Minister Dominique Voynet has said that the stormy conditions at the moment could mean the oil will continue to come ashore in small quantities for weeks.

Overnight winds of up to 140kph (85mph) could create waves of up to seven meters (23 feet) making the oil's course difficult to track.

Ports in the area have taken emergency measures, deploying floating barrages to protect them from the slicks.

Oil pollution could prove damaging for oyster farming, fishing and tourism in the area.

No disaster yet

Ms Voynet has said however that the situation was not yet an environmental disaster and that she hoped the pollution could still be contained.

Observers have predicted that the next coast to be affected will be the Bay of Bougneuf in the Vendee region.

Arguments continue to rage about who is to blame for the accident and how much damage it will cause.

Both parts of the Maltese-registered 24-year-old Erika remain on the sea bed with an estimated 16.3 million litres (4.3 million gallons) of oil still in its holds.

Maritime officials say they will not deal with that problem until the coastal threat has been dealt with.