Beijing has the "right and ability" to seize South China Sea islands occupied by other countries, a senior Chinese diplomat said Tuesday, ahead of regional summits expected to discuss the contested waters.

Beijing claims virtually the entire South China Sea and has sought to reinforce its position by rapidly constructing artificial islands capable of hosting military facilities.

Vietnam, the Philippines, Malaysia and Taiwan have competing claims and have also constructed smaller facilities on disputed islands in the Sea.

But vice foreign minister Liu Zhenmin told a briefing: "the Chinese government has the right and the ability to recover the islands and reefs illegally occupied by neighbouring countries".

"But we didn't do that, we exercised maximum restraint," he added.

China's island building has raised tensions with rival claimants and the United States.

Beijing said it was enraged last month when the USS Lassen sailed within 12 nautical miles of at least one of the artificial islets in the Spratlys chain.

Liu defended China's building of an airstrip long enough to accommodate military jets on one of the islands.

"Actually, the bigger the facilities, the more they can be used for civilian purposes," he said.

China has for years attempted to discourage South East Asian countries from collectively pushing their claims.

Beijing has said that the Asia-Pacific Economic Cooperation forum (APEC) taking place in Manila this week was "no place", to discuss the issue.

Earlier this month an Asia-Pacific defence ministers' meeting in Malaysia ended on a sour note as the United States and China butted heads over whether a final joint statement should mention the South China Sea.

Liu cautioned against the disputes becoming a focus for a forthcoming meeting of East Asian leaders in Malaysia.

"We hope that the East Asia Summit will not discuss the South China Sea," Liu said, adding that the issue had been "hyped up".