BORDEAUX (REUTERS) - Bordeaux vineyards in south-west France could lose about half of their harvest this year after two nights of frost damaged the crop at the end of April, a wine industry official said on Saturday.

Wines from the Cognac, Bergerac, and Lot-et-Garonne regions had also been affected, Bernard Farges, head of the Syndicat des vins Bordeaux et Bordeaux Supérieur, told Reuters.

"For Bordeaux wines...we estimate that the impact will be a loss of about 50 per cent, depend on how many buds can regrow," he said.

Including lost earnings at wine industry subcontrators, the total damage is estimated at one to 2 billion euro (S$3.06 billion), with wine production set to fall by about 350 million bottles.

Frost damage varied widely depending on the precise area, with some owners expected to lose only 15 to 30 per cent of their grape harvest, but others at risk of seeing their entire production wiped out.

Growers have resorted to using candles, heaters and even the down-draught from helicopters to try to save crops.

France's total wine output fell 10 per cent last year due to adverse weather conditions. Champagne was the worst hit, with the harvest down more than 20 per cent on the previous year due to spring frosts followed by other problems such as mildew.