SHANGHAI, China - General Motors Corp. will unveil a new pair of concept cars in its Chevrolet and Buick lines at this month's Shanghai Auto Show, GM China said Monday.

The cars will be among 40 vehicles the company and its Chinese joint venture partners plan to display as GM increasingly looks to China to offset sluggish sales and crippling legacy costs elsewhere.

GM said the concept cars include the latest version of the Chevrolet Volt, the company's extended-range electric passenger vehicle which was introduced in January at the North American International Auto Show in Detroit.

It said the Buick model was developed at GM's design and engineering center in Shanghai and would point to "possible future directions for the brand worldwide."

GM opened its first factory in China in 1998 and now operates seven joint ventures and two wholly owned foreign enterprises in the country. Along with five vehicle factories and one engine plant, the company has also launched an auto financing venture and a chain of dealerships.

Its China sales last year rose 32 percent to 876,747 vehicles, with joint venture Shanghai General Motors Corp. becoming China's top-selling domestic automaker with 365,400 vehicles sold.

GM said it also plans to display minivans and compact cars produced by its SAIC-GM-Wuling joint venture set up in 2005. Wuling's vehicles have become a mainstay of the company's China business, accounting for more than half of GM's total sales in China last year.

GM said models from the company's German Opel brand, Buick, Cadillac, Chevrolet and Saab will also be featured at the show, which runs April 22-28.