Regional differences in China's economic development, rather than an symbol of underdevelopment in traditional sense, is a secret weapon underlying the country's sustained high economic growth, according to a think tank with Peking University.

Liu Wei, head of the university's School of Economics, made the remarks Tuesday at the release of 2007 China Economic Growth Report, the fourth annual macroeconomic report by the university's Economic Research Institute since its establishment in 2003.

According to Liu, the comparative advantages enjoyed by a large country, together with the regional differences, has provided favorable conditions for China to maintain its fast GDP (gross domestic product) growth over a relatively long period, chinanews.com reported Tuesday.

In retrospect, Liu said China registered an average annual GDP growth of 9.7 percent over the past three decades, but also saw serious imbalances in its regional development, with the Special Economic Zones taking the lead and the coastal areas with good natural conditions coming second in becoming rich.

"Beijing, the capital, and Tianjin, and Hebei have witness rapid gowth, and provinces rich in natural resources but weak in industrial development, such as Inner Mongolia and Shanxi in north China, are also catching up in recent years." he added.

A small country with balanced development or less conspicuous regional differences may see slowed growth or even reach a recession after maintaining the momentum for 20 or 30 years, he said.

"But in China, the development gap may further boost the economy in the long term." Liu was quoted as saying.

With proper policies, the inland provinces and lagging-behind area will become the new drive for the country's growth in the 21th century, he predicted.

The country has just witnessed four consecutive years of double-digit growth, including 10.7 percent GDP growth last year, the fastest in a decade.