A US official on Wednesday voiced hope that China and Southeast Asian nations will start talks soon on a code of conduct to resolve disputes over the South China Sea after repeated flare-ups.

Joe Yun, the acting assistant secretary of state for East Asia, said that China and the 10-member Association of Southeast Asian Nations (ASEAN) made apparent progress during a working-level meeting last week in Bangkok.

"I think there seems to be an understanding that at a future date, maybe sometime this year, they will announce a formal beginning of negotiations" on a code of conduct, Yun told the Center for Strategic and International Studies.

"If that's the case, we would genuinely welcome it because we see CoC as a key piece of the puzzle that would bring peaceful resolution" to rival claims in the South China Sea, Yun said.

Tensions have soared in recent years as Vietnam and the Philippines accuse China of increasingly assertive claims to territories in the South China Sea, through which around half of the world's cargo passes.

The broader region is also rife with maritime disputes, with the Philippines and Taiwan recently at loggerheads and China and Japan embroiled in a bitter dispute over islands in potentially energy-rich waters of the East China Sea.

Yun reiterated that the United States does not take sides in territorial disputes and that a code of conduct, which would formalize rules of behavior, offered the best way to prevent further conflict.

"To be frank with you, I'm not sure that these territorial disputes, whether they are maritime or whatever, can ever be fully resolved in a sense that one party says, 'Damn, I think you're right, you know I never thought about that,'" Yun said.

Instead, the code of conduct can offer a way to "not disturb our stability," he said.