China is concentrating on civil - not military - construction on islands in the South China Sea and will expand land reclamation, Chinese experts said on Monday.

"Most of the construction on islands in the South China Sea were completed in 2015 and the pace then slowed. Civilian facility construction is the major focus of the South China Sea islands building and the portion of defense deployment is relatively small," Chen Xiangmiao, a research fellow at the National Institute for the South China Sea, told the Global Times.

China has almost finished transforming seven reefs in the South China Sea into "island fortresses," and the move is to "dominate" the South China Sea, according to an exclusive report published in the Philippine newspaper the Inquirer on Sunday.

The size of some South China Sea islands will be further expanded in future through more dredging in the South China Sea region, Chen said.

The relationship between China and other Southeast Asian countries, such as the Philippines, has becalmed in recent years, providing a golden opportunity for China to upgrade these areas, he said.

Singaporean Foreign Minister Vivian Balakrishnan told the Strait Times last week the South China Sea was "much more calm now," and that Singapore will help broker talks on a maritime code of conduct.

Balakrishnan's remarks reflect China's confident cooperation with Association of Southeast Asian Nations on maintaining regional peace and stability, Chinese foreign ministry spokesman Geng Shuang said on Monday.

China and the Philippines are enjoying good terms as President Rodrigo Duterte maintains a friendly policy toward China, Chen said. "But there is still some domestic pressure that urges Duterte to take a tough stance on China and the South China Sea issue," Chen said.

Foreign media liked to hype China's construction in the South China Sea as they try to make excuses to prevent China's activities in this region, Zhuang Guotu, head of Xiamen University's Southeast Asian Studies Center, told the Global Times.

"China has the right to build whatever it needs within its territory," Zhuang said.

China's military deployment in the South China Sea region was "not for military expansion," but to defend its security and interests, he said.

Zhuang and Chen warned the US is the biggest threat to stability in the South China Sea.

"The US, Australia, Japan and other allies will constantly provoke China over this issue and that will incite other neighboring South China Sea countries to do the same," Zhuang said.

China's construction projects in the region covered about 290,000 square meters in 2017, including new facilities for underground storage, administrative buildings and large radar, according to a report released in December on the nanhai.haiwainet.cn website run by the National Marine Data and Information Service and People's Daily Overseas edition.

The guided missile destroyer USS Hopper came within 12 nautical miles of Huangyan Island in January and Chinese missile destroyer Huangshan immediately drove it away, China News Service English service reported in January.

Newspaper headline: South China Sea islands foster civil construction