Bayerische Motoren Werke AG, the world's biggest luxury car maker, said its group vehicle sales in China grew by 31.5 percent in May, accelerating from 30.8 percent in April.

Over the first five months of this year, its sales in China rose 34.4 percent to 135,026 vehicles, BMW said on Tuesday.

BMW has said it plans to at least triple production in China to 300,000 vehicles, which still leaves it in the wake of rival Audi, which aims to expand production to 700,000 vehicles annually by around 2015.

China's burgeoning affluent class has transformed the global premium car industry by providing a seemingly limitless source of future demand.

Audi - the premium brand of Volkswagen - said earlier its vehicle sales in China jumped 44.2 percent in May.