Bullish sales of Buick, Chevrolet and Wuling vehicles boosted the market share, which expanded to an estimated 13.4 percent in 2009, up 1.3 percentage points from that in the previous year, according to the report.

Sales for GM's original brand Buick in China in 2009 surged 59.6 percent from a year earlier to 447,011 unites. The company's Chevrolet sales in China reached more than 330,000 units, up 67.1 percent year on year.

SAIC-GM-Wuling, GM's commercial vehicle tie-up with Shanghai Automotive Industries Corp (SAIC) and Liuzhou Wuling Automobile, sold more than 1 million vehicles in 2009, up 65.1 percent year on year, the report said.

GM China president Kevin Wale expected better performance on China's market this year, saying the GM would expand further but at a slower pace.

From January to November, China produced and sold more than 12.2 million cars, making it the world's largest auto market, the China Association of Automobile Manufacturers announced early this month.

The government has helped to shore up auto sales by cutting tax and providing subsidies to drivers shifting to cleaner, more fuel-efficient cars.

Since January, China has halved its vehicle purchase tax to 5 percent on vehicles with a displacement of less than 1.6 liters.

Two months later, a mini-vehicle incentive program in rural areas enabled buyers to enjoy up to 5,000 yuan in government subsidies for a vehicle with a displacement less than 1.3 liters.

Both policies, which are scheduled to expire on Dec. 31, have been approved by the State Council for an extension through 2010.