Many multinational companies have tapped benefits from the Asean Free Trade Area (Afta) as well as pacts with Australia and New Zealand that took effect this year. For instance, automobile companies are sourcing parts from different countries at low or no tariffs and in turn exporting assembled vehicles throughout the region and beyond, he said.

"Multinational companies are taking all the Asean privileges that we have among ourselves. Awareness therefore is the foremost challenge for Asean governments," Mr Surin said yesterday in Bangkok.

The six more developed economies of Asean have completely removed import taxes for Asean firms, while the four less developed members must do so by 2015.

Asean members are also working to improve road and railway links, such as Kunming to Singapore and Guangzhou to Bangkok, to make trade easier.

Singapore has eased customs procedures for goods transported from Thailand to Singapore via Malaysia. Customs formalities for goods bound from Thailand to Vietnam via Laos have also eased.

Yet the value of trade among the 10 Asean economies stood at just one-quarter of the members' total international trade, or $400 billion. Asean's exports to the rest of the world stood at $1.7 trillion per year, slightly more than the combined size of the 10 economies.

"The challenge is how to increase trade among ourselves. Governments can lay out a vision, but they don't have the nuts-and-bolts and tools to bring you there," Mr Surin said at the Asean Business Forum, held by the Thai Chamber of Commerce

Asean countries should also ensure that they build up the competitiveness of the private sector through R&D and English-language education to ensure they benefit from liberalisation of skilled labour movement, he added.

Asean countries are scheduled to completely remove obstacles in cross-border trade, investment and movement of eight occupations over the next six years.

Dean Thorpe, managing director of CEVA Logistics (Thailand), said Asean governments should offer clearer customs procedures as inconsistencies persist in many countries.

Kalin Sarasin, managing director of SCT Co, said Asean-based firms would benefit from a road network linking Burma to Vietnam and southern China to Malaysia.

But the challenge for Asean governments is to promote opportunities for smaller firms, as there were huge shortcomings in awareness of how economic integration could help or hurt them, he said.

"How can SMEs react to it? Do they know about it? What can they do if they know? How will the public sector administer under Asean integration? These are important questions facing Asean governments," said Mr Kalin.