Chinese Foreign Minister Yang Jiechi told his counterparts from around the the Asia Pacific at a security forum in Indonesia that tensions between China and its rival claimants to the sea would not affect vital shipping trade.

"What I told the summit is that freedom of navigation in this region is guaranteed," Yang said in a briefing to reporters after his speech.

"If there is no guarantee, how do we explain Asia's economy is fast developing in the world's economy? How do we explain Asia contributed to half of the world's economy recovery?"

China claims all of the South China Sea, where shipping lanes link East Asia with Europe and the Middle East.

But the Philippines, Vietnam, Malaysia, Brunei and Taiwan have overlapping claims to parts of the sea, and the decades-long dispute has intensified in recent months amid complaints of increased Chinese aggression in the waters.

The Philippines and Vietnam have accused China of acts such as harassing oil exploration vessels, shooting or beating up their fisherman, and placing territorial markers on islets in the sea.

US Secretary of State Hillary Clinton voiced concern at the same forum on the Indonesian island of Bali on Saturday that "recent incidents" in the sea were a threat to regional peace and free passage in the shipping lanes.

"These incidents endanger the safety of life at sea, escalate tensions, undermine freedom of navigation, and pose risks to lawful unimpeded commerce and economic development," Clinton said.

Philippine Foreign Secretary Albert del Rosario said Yang's comments on freedom of navigation offered little comfort because China maintained its hardline position that no other country had any rights to the sea.

"How can you discuss anything bilaterally when you sit down with them and they say that they own everything?" he said.

US Secretary of State Hillary Clinton said a deal between China and Southeast Asian nations on guidelines for future negotiations over the South China Sea was just a "first step" towards a binding code of conduct.

"We think it was an important first step but only a first step in adopting the declaration of conduct," Clinton told reporters in Indonesia after attending Asia's main security forum.

More detailed negotiations are needed to unpick a tangle of maritime stakes in the South China Sea, which China claims in its entirety despite rival assertions by Brunei, Malaysia, the Philippines, Taiwan and Vietnam, Clinton said.

"There needs to be a lot of dialogue between (Southeast Asian nations) and China... and the rest of the world needs to weigh in because all of us have a stake in ensuring that these disputes don't get out of control," she said.

Clinton noted the South China Sea carried about half of global trade and said the international community should be more involved in settling disputes, an idea China has repeatedly rejected while "guaranteeing" free navigation.

She said all territorial claims should be clearly defined and resolved according to the UN Convention on the Law of the Sea, a position shared by most of the claimants except China, which bases its stake on historical maps.

At a meeting with the 10 members of the Association of Southeast Asian Nations on Wednesday in Bali, China agreed to a set of guidelines setting a framework for an eventual code of conduct for the sea.

China and some ASEAN members hailed this as a breakthrough that would defuse the tensions, but the Philippines maintained the guidelines lacked teeth and did not specify what territory is in dispute.

Clinton said there had been increasing incidents of intimidation, rammings, and the cutting of exploration cables lately -- the "kind of things that will raise the cost of doing business for everyone".

"We are strongly against use or threat of force by any nation to advance its claims," she said.

"There needs to be very concerted effort to realise a code of conduct and there needs to be a call by the international community for all parties to clarify their claims."

Her comments are likely to irritate China, which has repeatedly warned the United States not to interfere in its territorial integrity and rejects international pressure to resolve its maritime disputes.

Clinton met Chinese Foreign Minister Yang Jiechi in Bali last week and repeated Washington's assertion that the United States has a "national interest" in free navigation in the sea.

Yang said later that he had reassured ministers from more than 20 Asia-Pacific countries gathered for the ASEAN Regional Forum that tensions between China and its rival claimants would not affect shipping trade.

"What I told the summit is that freedom of navigation in this region is guaranteed," Yang told reporters Saturday.

"If there is no guarantee... how do we explain Asia contributed to half of the world's economy recovery?"

In recent months, the Philippines and Vietnam have expressed anger over what they call China's increasingly aggressive actions in the potentially resource-rich sea, such as harassing fishermen and oil exploration vessels.

Philippine Foreign Secretary Albert del Rosario said Yang's comments on freedom of navigation offered little comfort because China maintained its position that no other country had any rights to the sea.

"How can you discuss anything bilaterally when you sit down with them and they say that they own everything?" he said in Bali Saturday.