SHANGHAI, Oct. 31 -- China is expected to replace the United States as the world's largest auto market by as early as 2020, according to a Chinese government official.

The nation will sell an estimated 20 million vehicles by 2020, exceeding 17 million sold in the United States annually, said Xu Changming, director and senior economist of the Information Resource Development Department of the State Information Center.

"We forecast most mid-class families can afford to buy cars in China by around 2009 as the massive production will result in cheaper car prices," said Xu at the 4th China Automotive Industry Forum organized by China European International Business School in Shanghai yesterday.

Total sales of vehicles will reach 7 million units this year, a rise of 25 percent year on year, helping China to beat Japan and move one notch forwards as the world's second-largest market.

"The demand in the market will continue for another 15 years and the annual sales growth would be 1.5 times than that of (China's) annual gross domestic product," Xu said.

China's auto industry is narrowing its sales gap with the more matured US market as an average 10 percent economic growth drives up car sales from a low automobile ownership base in a nation with a 1.3 billion population.

Sales of passenger cars including sedans, sports utility vehicles and multi purpose vehicles will amount to 4.2 million units after an average combined sales growth of 36 percent in the past six years.

Both overseas and domestic carmakers have raised their investment by adding capacity and launching new models to meet the growing demand.

The fast-expanding production and lower production costs have also prompted Chinese carmakers to increase their exports.

Auto exports will surpass 500,000 units next year after probably reaching 215,000 units this year, Xu said. He added the growth in exports has been doubling every year since 2002.