BEIJING - China plans to spend a further $21 billion on major industrial, transport and social projects to accelerate growth in its less developed western region, state media reported Monday.

China's top economic planning agency, the National Development and Reform Commission, had earmarked funds to undertake 12 top-priority projects, including investments in transport, mining, industry and health, according to reports carried by the official Xinhua press agency.

Much of this spending would be directed to poor rural areas in western China, where the government already devoted almost $125 billion on 70 major infrastructure projects in the five years to 2005, according to the commission.

China's rise as an export powerhouse has delivered unprecedented prosperity to regions along its eastern seaboard and lifted hundreds of millions of people out of poverty.

The central authorities fear, however, that a growing income gap between the relatively affluent cities in the east and the poor western regions could ignite further unrest.

The new spending announcement came as China celebrated the opening Saturday of the Qinghai-Tibet railway. The link is the world's highest railroad and connects remote, mountainous Tibet with the rest of the country. The newly completed final section to the Tibetan capital, Lhasa, covers 1,140 kilometers, or 700 miles, across the Kunlun and Tanggula mountain ranges and cost almost $3.7 billion to build.

The central authorities say the new line will bolster the economy of one of China's poorest regions through increased tourism, trade and investment.

"From a public policy point of view, the challenge is to create more opportunity for people left behind," said Qu Hongbin, chief China economist at HSBC. "By directing public works into poor western regions, they can indirectly narrow this income gap."

The move to spend more on public works in western China comes as the authorities have ordered curbs on overall growth in infrastructure investment to avoid economic overheating.

While parts of eastern China have some of the world's most advanced urban transport technology, like Shanghai's magnetic-levitation rail corridor, large tracts of western China lack the most rudimentary road and rail links.