The center, in the provincial capital of Chengdu, is the first of its kind in western China. Its opening is in response to the rapidly growing demand for investment in Hong Kong from companies in China's western regions, according to Invest Hong Kong (IHK).

The Chengdu center, like its counterparts in Guangzhou, Beijing and Shanghai, will offer free services, including market research and business advice, to support mainland companies investing or listing in Hong Kong.

The Chengdu center would target companies from the mid-western regions of Sichuan, Yunnan, Guizhou, Hunan, Shaanxi and Chongqing, said Mike Rowse, IHK's director general of investment promotion.

Chengdu was chosen for its resources of technology and skills, and sound transport networks to western regions, whose development had been given greater significance in the government's 11th Five Year Plan (2006-2010), said Richard F.C. Luk, director of the Hong Kong Economic and Trade Office in Chengdu.

Official figures show altogether 384.9 billion HK dollars was raised last year by 368 Hong Kong-listed mainland companies, including 22 from the six targeted western regions, 94 percent up from 2005.

Meanwhile, 282 mainland companies invested a total of more than two billion U.S. dollars in Hong Kong last year.

"Only one company from western China invested in Hong Kong last year," said Luk. "But there will be more in future as the economy grows."

Invest Hong Kong had helped 114 mainland firms invest in the past three years, and the number was expected to grow steadily in the next five years, said Rowse.