Prime Minister Lee Hsien Loong arrives here today to meet fellow South-east Asian leaders for the 31st Asean Summit.
He will be in the Philippine capital until Tuesday, and will attend meetings between Asean leaders and those of China, the United States and key regional partners including India, Japan and South Korea.
The leaders will take stock of the implementation of the Asean Community and discuss how to take it forward, the Prime Minister's Office said in a statement.
The 10 Asean members are set to sign a document pledging their commitment to protecting and promoting the rights of migrant workers.
They will also announce the official start of negotiations with China on a code of conduct to manage disputes in the South China Sea. A framework which lay the groundwork for negotiations on the code was adopted in August.
Asean will also hold special summits with the US, Canada and the European Union to mark the 40th anniversary of relations with each.
Accompanying PM Lee are Mrs Lee, Foreign Minister Vivian Balakrishnan, Minister for Trade and Industry (Trade) Lim Hng Kiang and officials from their ministries.
Trade will be high on the agenda. Today, Asean will sign two free trade and investment agreements with Hong Kong, the bloc's sixth largest trading partner. Negotiations for the deals, which will strengthen economic cooperation between Asean and Hong Kong, were launched in 2013 and concluded this July. They are expected to be ratified in two years.
Also on the table is the Regional Comprehensive Economic Partnership (RCEP) being negotiated between Asean and six of its key trading partners: Australia, China, India, Japan, South Korea and New Zealand.
Mr Lim and his counterparts will take stock of the status of talks on the RCEP ahead of a formal leaders' meeting on Tuesday.
Singapore takes over as Asean chair next year, and the Philippines will hand over the symbolic gavel to Singapore at the summit's closing ceremony on Tuesday. PM Lee will also outline Singapore's priorities as Asean chair then.
In his absence, Deputy Prime Minister Teo Chee Hean is Acting PM.