Experts said upgrading the China-ASEAN Free Trade Area requires building an area for closer, freer and comprehensive economic and trade cooperation.

"The agreement shows the region closely relies on China's economic vitality on the basis of the two sides properly responding to the international financial crisis," said Liu Jiangyong, a professor of international relations at Tsinghua University.

Liu said cooperation, for example on lowering tariffs and providing more convenient logistics, will increase bilateral trade and people-to-people exchanges.

"The more open and inclusive integration will provide new opportunities for ASEAN economies and push forward China's economy, especially driving development in southwest China," Liu said.

But, as the world's second-largest economy, China's direct investment in ASEAN is lagging. By the end of June, its direct investment in the regional bloc was nearly $30 billion, while direct investment from ASEAN into China exceeded $80 billion.

Zhang Yunling, a researcher from the Chinese Academy of Social Sciences, said: "In the past decade, bilateral trade in goods has seen a breakthrough. The further evolution of bilateral relations exists in extending a more comprehensive partnership, such as more service trade cooperation and opening up investment.

"The upgraded version of the China-ASEAN Free Trade Area will bring some changes in the bilateral trade structure because the volume of service trade will be underlined."

Premier Li proposed an upgraded version of the free trade area at the opening ceremony of the 10th China-ASEAN Expo and the China-ASEAN Business and Investment Summit in Nanning in September.