CHALLENGES LYING AHEAD

While seeing the enormous opportunities offered by the ASEAN Community, officials and analysts don't underestimate the challenges lying ahead.

For ASEAN, there is still a long way to go to complete the building of the ASEAN community, Xu said.

"The community building is always an ongoing process and Dec 31 of 2015 is definitely not an end but a starting point," the ambassador said, adding China is willing to play a constructive role and work with ASEAN to push for the complete realization of the ASEAN Community.

Some experts expressed worries that the AEC may face challenges as economic and social development varies among ASEAN members.

"Some ASEAN members thought integration may harm the interest of their small- and medium-sized enterprises. For instance, Cambodia worried that its enterprises may suffer when competing with companies from other countries a few years ago. But nowadays, the momentum of regional economic development is quite satisfying," said Lee.

Lee said frequent communication and interaction will help to overcome difficulties, and ASEAN members can learn from each other.

The experts also noted that China's Belt and Road Initiative will inject new momentum into ASEAN's development, as the initiative emphasizes interconnectivity. Besides, China is a huge market for ASEAN members, which will have more options as China's market widens.

Agreeing with Lee, Vo Dai Luoc, former director of Vietnam's Institute of World Economics and Politics, said that in order to narrow development gaps among ASEAN members, they should strengthen integration for development as well as cooperation with international organizations and the block's non-member countries and partners, including China.