Not afraid of US ‘provocations’, says China

China on Sunday hit out at US "provocations" and said it does not fear "trouble" over its territorial disputes with neighbours in the South China Sea.

"The South China Sea issue has become overheated because of the provocations of certain countries for their own selfish interests," Admiral Sun Jianguo told a security summit in Singapore.

Sun spoke one day after US Defence Secretary Ashton Carter warned that Chinese construction on a South China Sea islet claimed by the Philippines would prompt unspecified "actions" by the United States and other nations.

On a visit to Mongolia on Sunday, Secretary of State John Kerry also warned Beijing against setting up an air defence identification zone over the disputed waters, saying it would be a "provocative and destabilising act".

Rhetoric has escalated ahead of a ruling from the Permanent Court of Arbitration in The Hague on a case brought by the Philippines, a long time US ally and former colony, against China, which has shunned the proceedings and says it will not recognise any ruling.

The Chinese admiral, in a clear reference to Washington, said "freedom of navigation" patrols in the South China Sea were a display of "military muscles" and that China was being forced to "accept and honour" the tribunal's ruling.

"China firmly opposes such behaviour. We do not make trouble but we have no fear of trouble," Sun, the head of the Chinese delegation to the Singapore forum known as the Shangri-La Dialogue, said in prepared remarks.

In an open forum, he addressed Pentagon chief Carter's statement on Saturday that Beijing risks building a "Great Wall of self-isolation" with its military expansion in the contested waters.

"We were not isolated in the past. We're not isolated, and we will not be isolated in the future. Actually I am worried some people and countries are still looking at China with a Cold War mentality and prejudice," the Chinese admiral said in response questions from other delegates.

"They may build a wall in their mind and end up isolating themselves," he said.

In his speech, Sun said, "any countries that are not directly concerned are not allowed to sabotage our path of peace for selfish gains".

Hong Kong's South China Morning Post has reported that China plans to establish an outpost on Scarborough Shoal, located 230 kilometres off the Philippines, which considers it part of its exclusive economic zone.

Beijing claims nearly all of the strategically vital sea and has developed contested reefs into artificial islands, some topped with airstrips.