ASEAN should forge a common position on a proposed code of conduct aimed at easing tensions in the South China Sea before talking with China, Philippine President Benigno Aquino said Tuesday.

Aquino told fellow leaders of the Association of Southeast Asian Nations that the fundamentals of the proposed code should be "internal" to the regional bloc's members, according to a statement from the Philippine foreign ministry.

"It is important that we maintain ASEAN centrality," Aquino said at the annual ASEAN summit in the Cambodian capital Phnom Penh.

"After the CoC (code of conduct) has been finalised by ASEAN, then ASEAN member states will meet with China."

Philippine Foreign Secretary Albert del Rosario said there was a "big disagreement" at a session earlier when ASEAN Secretary General Surin Pitsuwan announced that China might be invited to take part in the drafting of the code.

"We are saying that we're happy to invite China but this should be done after the approval of the CoC (by ASEAN). I think that we should be masters of our own destiny as far as the CoC is concerned," del Rosario told reporters, adding that Vietnam expressed a similar sentiment.

He said that it would be difficult for ASEAN -- which operates by consensus -- to have all of the 10 members agree on inviting China to be involved in the code's drafting.

"I believe that they need to have consensus if they are going to pursue this and they will not have consensus," del Rosario said.

"We are trying to do it as fast as we can, but what we are objecting to is we don't want China to be invited in terms of the drafting and the decision making."

Asked which countries wanted China to take part, he said: "I think Cambodia would be one of them." Cambodia is the current chair of ASEAN's rotating leadership.

During Indonesia's chairmanship of the regional bloc least year, ASEAN and China agreed on a set of guidelines for the proposed code, ending a nine-year impasse.

The code is envisioned to be a legally binding document aimed at preventing small incidents in the South China Sea from escalating into bigger conflicts that could draw in major world powers like the United States.

ASEAN members Brunei, Malaysia, the Philippines and Vietnam along with non-members China and Taiwan have overlapping claims in the South China Sea, a conduit for more than one-third of the world's seaborne trade and half its traffic in oil and gas.

The Philippines and Vietnam accuse China of aggressively asserting its claims in recent years. The United States meanwhile asserts a "national interest" in keeping the sea's shipping lanes free and open.

Surin, the ASEAN chief, said recent clashes have "given a sense of urgency" on efforts to try to resolve the disputes.

"It has given the global community a sense of concern that this could lead to open conflict which will not be in the interest of any party," Surin said in an interview with AFP.

"So we have the support of the international community to resolve this problem peacefully, effectively as soon as possible and we are working on it."

The South China Sea will be a key issue during the ASEAN Regional Forum, a security-focused meeting held annually in July involving ministers from 27 countries, including the United States, China, India, Japan and Australia.