Myanmar's recent elections, North Korea's planned rocket launch and maritime disputes with China are set to dominate the agenda of the Association of Southeast Asian Nations (ASEAN) which has begun in Phnom Penh.
The summit of the 10-member ASEAN bloc commenced in the Cambodian capital on Tuesday, just two days after by-elections in Myanmar saw pro-democracy leader Aung San Suu Kyi win her first seat in parliament.
ASEAN foreign ministers applauded the "orderly" conduct of the polls during talks in Phnom Penh on Monday, setting the stage for a strong endorsement from the bloc's leaders at Wednesday's conclusion of the two-day summit.
Representing almost 600 million people from disparate economic and political systems, the ASEAN bloc comprises Brunei, Cambodia, Indonesia, Laos, Malaysia, Myanmar, the Philippines, Singapore, Thailand and Vietnam.
Surin Pitsuwan, the ASEAN secretary-general, said the vote should contribute to the "reintegration of Myanmar into the global community", a reference to the possible lifting of sanctions.
Election monitors from Cambodia, which holds the ASEAN chair, have declared Sunday's vote free and fair, and have urged the West to lift sanctions imposed over the Myanmar military's long record of rights abuses.
Myanmar's human rights abuses and iron-fisted suppression of political dissent have often hijacked ASEAN gatherings in the past, much to the embarrassment of more democratic member-states.
But over the past 12 months the country's quasi-civilian government, led by President Thein Sein, has freed hundreds of political prisoners, eased media restrictions and welcomed the opposition back to the political fold.
At the last ASEAN summit in November, the country was rewarded for its efforts by being promised the bloc's chairmanship in 2014. Myanmar is eager too to win greater foreign investment with the prospect of sanctions being lifted.
North Korea's planned rocket launch, described by Pyongyang as a bid to send a satellite into orbit but condemned by the United States and its allies as a thinly disguised missile test, is also on the the agenda for the Cambodia summit.
Albert del Rosario, the Philippine Foreign Secretary, said the ASEAN foreign ministers spoke with one voice against the nuclear-armed North's launch plans.
The Philippines, which lies beneath the rocket's proposed flight path, has lodged formal protests with Pyongyang's representatives at the United Nations, in China and at ASEAN.
"I think the countries that spoke on the topic ... were all of the opinion that we should be discouraging (North Korea) from undertaking that launch," Del Rosario said after the foreign ministers' meeting on Monday.
Regional tensions with China over disputed islands in the South China Sea are another vexing issue for the ASEAN leaders, diplomats said.
China has competing territorial claims in the sea with ASEAN members Brunei, Malaysia, the Philippines and Vietnam.
The US says it has a "national interest" in keeping the vital trade route open to shipping.
The sea is a conduit for more than one-third of the world's maritime trade and half its traffic in oil and gas, and major petroleum deposits are believed to lie below the seabed.
US ally the Philippines has been leading a push for ASEAN to form a united front and present China with a binding "code of conduct" in the sea, but other members argue that Beijing should be involved from the start.
There are also differences over the "internationalisation" of the rival claims, with Cambodia insisting they are matters for quiet diplomacy between ASEAN and China but the Philippines asserting the primacy of international law.