Asean is moving towards its vision of a "good solid" Asean Community by end 2015 of a single market and a region that is competitive and plugged into the world, Prime Minister Lee Hsien Loong said on Thursday as he addressed fellow leaders at the 22nd summit in Brunei.

He urged all the Asean 10 to press on with pledges to integrate their economies, saying this will "increase opportunities for Asean member states to prosper and reduce the likelihood of conflict".

The regional bloc's achievements this year have been steady, he said, despite a backdrop of looming uncertainty with slow growth in the global economy, hotspots in Asia that could turn into conflicts and the evolving strategic relationship between the United States and China.

Within Asean itself, the top security issue is the South China Sea, where China and four member states, the Philippines, Vietnam, Malaysia and Brunei, have overlapping territorial claims.

The South China Sea is "one major test of Asean credibility", Mr Lee said even as he welcomed the consensus reached at this summit on Asean's readiness to start negotiations with China on a Code of Conduct, with the aim of averting unintended mishaps or clashes at sea that could cause tensions to escalate.

While the fundamental issue can only be resolved in the long term, that all Asean 10, including the claimant states, have agreed on the Code of Conduct is significant, Mr Lee said. "This is a step forward. It doesn't mean we have solved the problem or that we are totally identical in our views but at least on that basic principle we have reached basic consensus," he added.

Mr Lee also praised Brunei, this year's Asean chairman, for doing a good job in coordinating the meeting, building a consensus among members and taking an even-handed view of the issues.