Audi could halt production of its high-end luxury vehicles early next year if a slump in western European auto markets worsens, Audi's top labour leader told Reuters.

German premium car makers have been considered immune to the crisis buffeting Europe’s volume carmakers but slowing economic growth and persistent unemployment is keeping customers out of the showrooms.

Audi has already twice stopped the line for a week at its second-biggest plant in Neckarsulm in early and late October affecting production of models including the A7 coupe, the A8 sedan and R8 sportscar.

Audi works council chief Peter Mosch told Reuters: “Should the market situation deteriorate considerably at the start of next year, then it is possible that further action may have to be taken.”

Possible stoppages could also hit Audi's main plant in Ingolstadt at some stage, Mosch said. The company produces about 1,200 cars a day in Neckarsulm and about 2,500 in Ingolstadt.

Research firm IHS Automotive believes that production in Neckarsulm could fall 6.8% next year to 243,348.

Reuters noted that Audi, which accounts for almost half of VW group's operating profit, is not the only luxury car maker to address weak demand.

Daimler last month cut production of its flagship S-Class until the next version of the model was ready to debut in mid-2013. Porsche plans to cut Saturday shifts from January at its main factory in Zuffenhausen which assembles the 911 model and the Boxster/Cayman.

At the Paris show in September, Audi chief executive Rupert Stadler said that the European car market may stagnate in the next year or two.