Brunei will pursue a binding code of conduct among competing South China Sea claimants as a top priority during its ASEAN chairmanship, officials said Monday.

The tiny, oil-rich Muslim sultanate has assumed the chair of the 10-member Association of Southeast Asian Nations (ASEAN) for 2013 at a time when tension over sweeping Chinese claims to the sea have rattled the region.

"Brunei sees this as a key threat to regional security and would like to resolve the issue through dialogue with all claimants, including China," said a foreign ministry official, who declined to be named.

ASEAN members Vietnam, the Philippines, Malaysia and Brunei, as well as Taiwan, also have claims to parts of the sea, one of the world's most important shipping lanes and believed to be rich in fossil fuels.

Simmering tensions over the issue have risen in the past two years, with the Philippines and Vietnam accusing China of becoming increasingly aggressive in staking its claims.

Cambodia's 2012 ASEAN chairmanship was marked by sharp regional discord over the affair.

The rancour led to unprecedented infighting at an ASEAN foreign ministers' meeting in Phnom Penh in July, which ended for the first time in the bloc's 45-year history without a joint communique.

As chair, Cambodia -- a close China ally -- was accused of resisting efforts by the Philippines and Vietnam to take a more aggressive position against the Chinese.

Efforts to secure a legally binding code of conduct involving ASEAN and China have floundered for years amid Beijing's insistence on handling disputes bilaterally with individual countries, while ASEAN wants to speak as a group.

China and ASEAN signed a broad declaration in 2002 pledging the parties would handle disputes peacefully and not take actions that threaten peace and stability.

During an ASEAN summit in November, the organisation called on China to get serious in working toward a binding code of conduct.

Brunei will host ASEAN leader summits in April and October.