Indonesia's President Susilo Bambang Yudhoyono Friday stressed the importance of safety and stability in the strategically vital South China Sea, as he opened an ASEAN summit with China.

A territorial dispute over the strategic region is expected to dominate talks on the Indonesian island of Bali over the next two days, attended by the United States and China, who have already wrangled over the issue.

Four members of the Association of Southeast Asian Nations (ASEAN) have competing claims over parts of the sea, while China claims it all, as does Taiwan, and there have been a number of incidents there this year.

Opening the ASEAN-China summit, Yudhoyono spoke of "the importance of security and stability in the South China Sea" and hoped for "a joint perspective on the importance of security and stability" in the area.

The maritime region is believed to encompass huge oil and gas reserves, and more than one-third of global seaborne trade passes through it.

The Philippines and Vietnam, both ASEAN members, have accused China of increasing aggression in staking its claim.

Hanoi said Chinese marine surveillance vessels cut an oil survey ship's exploration cables, while Manila has accused the Chinese military of firing on Filipino fishermen and harassing an oil exploration vessel in its waters.

The US has signalled it will raise the issue at Saturday's wider East Asia Summit despite Beijing insisting it is not an appropriate topic for discussion.

ASEAN and China adopted a non-binding "declaration of conduct" (DOC) in 2002 to discourage hostile acts. But attempts to transform it into a legally binding "code of conduct" (COC) have so far eluded agreement.

"On the area of political and security cooperation, we warmly welcome the acceptance of guidelines of the DOC in Bali in July 2011," Yudhoyono said.

"We all hope the guidelines will further encourage a joint perspective on the importance of security and stability in the South China Sea."

Progress on developing the code of conduct has been slow, with Beijing preferring to negotiate one-on-one with its weaker neighbours.

"Process of implementation of the DOC has begun and there will soon be the initiation of the discussion on the COC," Indonesian Foreign Minister Marty Natalegawa said after the meeting.