ASEAN, which has gained new relevance as a stage for international diplomacy, risks losing its sparkle as its least developed members prepare to take the bloc’s helm, analysts say.

The Association of Southeast Asian Nations, an unwieldy collection of democracies, monarchies and dictatorships, had in the past been dismissed as a “sunset organisation” hobbled by a non-interference policy in members’ affairs.

But far from being a “talking shop”, this year’s summit of the 10-member group, and the associated 18-nation East Asia Summit which includes the US and China, saw frank discussion on a highly sensitive territorial dispute.

After the assertive chairmanship of Vietnam and Indonesia over the past two years however, the blow will now be led by autocratic and underdeveloped Cambodia, the tiny sultanate of Brunei and military-dominated Burma.

“The chairmanship of ASEAN by its smaller and less-developed countries will be a challenge,” said Ernest Bower, director of the Southeast Asia programme at the Washington-based Center for Strategic and International Studies.

“Their turns come during what should be a historic turning point for ASEAN.” The group has an alphabetical rotating chairmanship but the order was thrown out when two members swapped, and by the inclusion of Burma, which was granted a 2014 slot as a reward for fledgling reforms.

The succession of minors comes as a 2015 target for full economic integration looms, and as the bloc hopes to cement its status as a powerbroker by bringing together its dialogue partners China and the United States.

There are concerns that impoverished countries lacking in expertise and democratic institutions will not have the ability to push ASEAN towards economic integration and global relevance.

“The moment of truth has arrived for ASEAN and it must now make choices about institutionalising and vastly enhancing its capacity, or risk slipping backwards into relative irrelevance,” Bower said.

ASEAN’s increasing effectiveness has coincided with a push by the United States to turn its gaze towards the strategic and dynamic Asian region, as it withdraws from theatres of war in Iraq and Afghanistan.

US President Barack Obama used this year’s summits on the Indonesian island of Bali to showcase that policy, challenging a clearly dismayed China on the South China Sea dispute, over which several regional nations have claims.

Obama, the first American president to attend the meeting, backed the East Asia Summit as a forum for resolving regional disputes — much as the Asia-Pacific Economic Cooperation (APEC) meeting is a venue for tackling economic issues.

He also unveiled a new US engagement with Burma, announcing that Secretary of State Hillary Clinton would visit next month to “empower” glimmers of reform in the country long ruled by the military.

Bower said ASEAN must now take advantage of this newfound acknowledgement by exerting control over its members, which often cite the bloc’s non-interference policy as an excuse to delay promised political and economic reforms.

“There really is no choice,” he said, noting that individual countries must “divest some elements of sovereign control to their regional identity.”

Pavin Chachavalpongpun, from Singapore’s Institute of Southeast Asian Studies, said that under ASEAN conventions there was no backing away from Burma chairing the grouping. “ASEAN will now have to hope that there would be more reforms on the way until 2014,” he said.

The Philippines, a leading voice in the push for change in Burma, said it remained optimistic ASEAN would continue to play a key role regardless of who is chair.

“ASEAN, with its theme of centrality, can perhaps be a staging ground for dialogue and is providing a venue for formally and informally interacting with each other,” said Ramon Carandang, spokesman of President Benigno Aquino.

“The idea that one country or another taking over the chairmanship of ASEAN is going to radically shift the direction of the group is, I think, not very accurate in our view.” Tiny states such as oil-rich Brunei have pulled off creditable summits in the past, but the diplomatic demands have increased dramatically since then and so has the size of the delegations including the enormous US security juggernaut.

Some regional capitals have limited hotel rooms, potholed streets, wobbly mobile networks and poorly staffed foreign ministries unprepared for the task that faces them.

ASEAN secretary-general Surin Pitsuwan conceded that the “personality and quality” of leadership under Indonesia, the bloc’s strongest democracy, was a major factor in the bloc’s bright new image.

“The framework, principles and momentum have been very good and we hope it is strong enough in different ways that it will help propel the process along,” he said of the possibility of a shift in pace over coming years.