The organization's 14th summit, held under the slogan "Acting Together to Cope With Global Challenges," will bring together the leaders of Brunei, Cambodia, Indonesia, Laos, Malaysia, Burma, the Philippines, Singapore, Thailand and Vietnam.
The participants will focus on ways to stabilize the region's economy and overcome the global financial crisis. The agenda will include the discussion of ways to reform the international financial system and expanding the representation of developing countries.
The summit, originally scheduled for December, was postponed twice amid national anti-government protests in Thailand demanding the resignation of Prime Minister Samak Sundaravej, who was ousted after mass protests in November that shut down Bangkok's airport.
The current prime minister, British-born Abhisit Vejjajiva, who took office after Sundaravej's resignation, has drawn anger from the supporters of former Prime Minister Thaksin Shinawatra, who say he gained power undemocratically.
Hundreds of supporters of Shinawatra, who was deposed in a bloodless 2006 coup, gathered on Friday near the hotel hosting the summit, demanding Vejjajiva's resignation and early elections.
Anti-government demonstrations have been held since late March. The latest rally was staged on Wednesday in central in Bangkok. The prime minister declared Friday a public holiday to help cope with the protests.