HONG KONG (Reuters) - China is worried it could face fresh criticism over its actions in the South China Sea when Singapore becomes chairman of the Association of South East Asian Nations next year, and is putting pressure on the city-state to make sure that doesn’t happen, according to people familiar with the situation.

They say that Chinese representatives have told Singapore counterparts in private meetings over recent months that they don’t want trouble for Beijing when Singapore takes over the annual leadership of the 10-nation group in 2018.

Diplomats say they believe that Beijing has used its influence over countries who have chaired ASEAN in the past to dilute the group’s stand on the South China Sea row, potentially one of the most volatile disputes in Asia.

The current chairman is the Philippines, which hosted the group’s foreign ministers last weekend. ASEAN failed to issue its customary statement on Saturday because of what diplomats said was disagreement about whether to make oblique references to China’s rapid expansion of its defense capabilities on artificial islands in disputed waters. The statement was finally issued on Sunday.

A Beijing-based Asian diplomat familiar with the situation said there are concerns that Singapore could use the ASEAN chairman position to try to “internationalise” the South China Sea issue, when China wants it limited to the countries directly involved.

“China thinks Singapore, as a Chinese-majority nation, should listen a bit more to Beijing,” the source, speaking on condition of anonymity, told Reuters.

“Beijing has made it very clear to Singapore what it expects on the South China Sea issue,” said another Asian diplomat in Hong Kong who is familiar with the situation.

Singapore’s Ministry of Foreign Affairs declined to comment for this story.

In a statement sent to Reuters, the Chinese Foreign Ministry said China supported Singapore’s work and “believes Singapore will lead ASEAN to work with China to promote the raising and upgrading of practical cooperation...and build an even closer China-ASEAN community of common destiny”.

FILE PHOTO: One of nine Terrex armoured vehicles, which belong to Singapore, waits to be loaded onto a truck at a cargo terminal in Hong Kong, China January 26, 2017. REUTERS/Bobby Yip/File Photo

Singapore is not a claimant to any disputed part of the South China Sea but is home to the biggest port in Southeast Asia, and has made clear its open economy depends on continued free navigation in the area.

China claims almost the entire sea, which includes one of the world’s most busy trade routes and sits stop valuable oil and gas reserves. Taiwan and four ASEAN states - the Philippines, Vietnam, Brunei and Malaysia - have overlapping claims.

The United States says it does not have a position on the South China Sea dispute but will assert freedom of navigation rights in the waterway.

BACK ON TRACK

Chinese Foreign Minister Wang Yi told his Singaporean counterpart Vivian Balakrishnan during a meeting in Manila on Sunday that ties had come back on track of late.

“Relations between China and Singapore have experienced ups and downs. But close exchanges between the two countries’ leaders recently have enhanced mutual trust, which is essential to healthy bilateral relations between China and Singapore,” Wang said, according to China’s foreign ministry.

Balakrishnan said the tone of his meeting with Wang was positive, Singapore media reported.

The worry for China is that Singapore has long-standing defense relationships with the United States and its allies, although the city-state says it is equally friendly with Beijing.

China is Singapore’s largest trading partner, and Singapore has been China’s largest foreign investor.

The United States and Singapore announced an enhanced defense relationship in late 2015, which included deployments of long range P-8 surveillance planes out of Singapore - aircraft which frequently track Chinese submarines.

Singapore also has some ties with Taiwan, which Beijing regards as a breakaway province.

Tensions between the two countries burst into the open last November when Hong Kong port authorities impounded nine Singaporean armored military vehicles being shipped home from training grounds in Taiwan. Hong Kong released the vehicles earlier this year amid rare open debates in both Singapore and China about a deteriorating relationship.

The Global Times, an influential state-run Chinese tabloid, said in June that the once “special relationship” between the two nations was fading away amid mistrust over the South China Sea.

Eugene Tan, an associate professor of law at the Singapore Management University, said there could be differences between the countries once Singapore takes over the ASEAN chairmanship.

When that happens, “China may be less able to force its way with Sino-ASEAN relations,” said Tan, who is a former Singapore foreign service officer and a former nominated member of parliament.

“Singapore is not in a position to tell other countries what to do in regards to their sovereignty but I think we can expect Singapore to take a very robust approach to dealings with China in its capacity as the ASEAN chair.”

Singapore Prime Minister Lee Hsien Loong has stressed the importance of abiding by international rules in the South China Sea despite China’s rejection of a ruling by the Permanent Court of Arbitration in The Hague that invalidated Beijing’s claims.

Zhang Baohui, a mainland security expert based in Hong Kong, said China questions whether Singapore is sincere when it says it didn’t want to choose between the United States and China.

“There is a view in Beijing that Singapore is the instigator of anti-China containment policies, not just within ASEAN but also that it wants a ring of pro-U.S. partners surrounding China – Japan, India and Australia,” he said.