MANILA - Asean leaders gather in Manila this weekend for the 30th Asean Summit, as the grouping celebrates its golden jubilee this year.

Singapore Prime Minister Lee Hsien Loong arrived in Manila on Friday (April 28) evening, and will join fellow Asean heads for a full day of meetings on Saturday.

During their meetings, Mr Lee and his counterparts are expected to discuss ways to strengthen Asean and ensure the grouping remains united as well as firmly in control of developments in Southeast Asia.

This focus on Asean centrality and unity comes as the grouping becomes more interconnected with the establishment of the Asean Economic Community in 2015.

The 10 member nations of Asean signed a milestone agreement that year - the Asean Community Vision 2025 - pledging to work towards greater market integration and political, security and socio-cultural cooperation.

Leaders will take stock of the grouping's progress towards that goal when they meet.

The Prime Minister's Office said in a statement on Friday that the leaders will also exchange views on Asean's external relations and discuss regional and international issues.

Among the issues likely to crop up is the rising tension in the Korean peninsula.

Asean foreign ministers have expressed concern after North Korea held a missile test earlier this month (April) and also threatened to launch a nuclear strike on Australia.

Terrorism is also likely to be on the agenda, as is the need to open up trade across the region at a time when protectionist sentiment is on the rise globally.

Asean secretary-general Le Luong Minh said in an interview that leaders of the grouping have also instructed officials to try to conclude a region-wide trade pact by the end of this year.

The leaders will also take stock of progress on the Regional Comprehensive Economic Partnership (RCEP) when they meet.

Asean was founded by Indonesia, Malaysia, the Philippines, Singapore and Thailand in 1967, to promote peace, understanding, cooperation and development among South-east Asian nations.

Over the years, it has grown to include Brunei, Cambodia, Laos, Myanmar and Vietnam.

As of 2015, Asean had a combined gross domestic product of US$2.4 trillion (S$3.3 trillion), making it the world's fifth largest economy behind the United States, the European Union, China and Japan.

The meeting between Asean leaders in Manila is the first of two that Philippines will host as Asean chair this year.

It will host another series of meetings in November, which are traditionally attended by Asean's key partners. Last week, US Vice-President Mike Pence said on a visit to the Asean secretariat in Jakarta that US President Donald Trump will attend the US-Asean Summit and East Asia Summit in the Philippines this year.

Minister for Foreign Affairs Vivian Balakrishnan is accompaning PM Lee at the summit.

Deputy Prime Minister Teo Chee Hean will be the Acting Prime Minister in Mr Lee's absence.