NANNING, Jan.8 -- China's investment in southeast Asia will rise rapidly as firms become more eager to go abroad with economic recovery, a senior commerce official said Thursday.

Both China and the Association of Southeast Asian Nations (ASEAN) should make full use of investment funds and other resources and step up infrastructure construction to meet the need of further trade cooperation, said Vice Commerce Minister Yi Xiaozhun at the ceremony marking the establishment of China-ASEAN Free Trade Area.

The CAFTA, the world's largest free trade area of developing countries, started operation on Jan. 1. It covers a population of 1.9 billion and accounts for about 4.5 trillion U.S. dollars in trade volume.

 "The FTA is mutually beneficial," Yi said. "With full consideration of economic development levels and market capacities of both sides, the FTA will advance the regional economic integrity by eliminating barriers of trade and investment."

Under the FTA, the average tariff on goods from ASEAN countries to China is reduced from 9.8 percent to 0.1 percent. The six original ASEAN members -- Brunei, Indonesia, Malaysia, the Philippines, Singapore and Thailand -- slashed the average tariff on Chinese goods from 12.8 percent to 0.6 percent.

By 2015, the policy of a zero-tariff rate for 90 percent of Chinese goods is expected to extend to the four new ASEAN members, Cambodia, Laos, Myanmar and Vietnam.

China helped the southeast Asian countries out of the 1997 Asian financial crisis and now they were working actively together to cope with the current global financial crisis. The ASEAN put more trust in China amid the unstable world economy, said Somesavat Lengsavad, Lao Deputy Prime Minister, at the ceremony.

The establishment of the FTA will greatly promote the cooperation in trade, investment and tourism of both sides, thus helping narrow the economic gaps between ASEAN members, he said.

Despite the financial crisis, the ASEAN remained China's fourth largest trade partner, following the European Union, the United States and Japan. China rose to become Singapore's second largest trade partner and the first for Malaysia in 2009.