Squabbling over membership of the new 16-nation East Asia Summit, which includes economic powerhouses China and India, is divisive and could thwart regional cooperation.

"The question of who should be included and who should be excluded continues to be asked," Malaysian Prime Minister Abdullah Ahmad Badawi said in a keynote speech to a conference on East Asian cooperation.

"We cannot seek to be continually moving the boundaries of consensus and agreement. Community building and regional cooperation cannot proceed smoothly in such an environment."

The East Asia Summit, which embraces the 10-nation Southeast Asian bloc, its dialogue partners China, Japan and South Korea as well as Australia, India and New Zealand, met for the first time last December.

But the summit took place amid wrangling over its membership, with the controversial inclusion of Australia, India and New Zealand because of concerns that China could dominate the discussions in the absence of the United States.

Russia wanted to join too, but was knocked back by Asean, which was worried membership was becoming too wide.

Abdullah said he expected the membership issue to be raised at the Association of Southeast Asian Nations (Asean) annual meeting and second East Asia Summit next week in the Philippines.

Stepping stone

The new grouping is seen as a stepping stone to a mooted European-style East Asia Community, which would create a sweeping free-trade zone taking in half the world's population.

Asean has sought to downplay suggestions that the East Asia Summit, described as a strategic dialogue forum, would become the pre-eminent grouping for the region.

Abdullah reiterated that Asean's near decade-old ties with its three dialogue partners would continue to be the driving force for building an East Asian community.

The East Asia Summit, as well as Asean's relations with individual countries would "play a supporting role", he said, warning that "endless and unproductive debate" over which forum should take precedence would create regional rifts.

"We run the risk of increasing the competition for spheres of influence and factionalising the region," he said.