HAIKOU - China will build an offshore supervision platform to help with the protection of cultural relics around the Xisha Islands in the South China Sea, local authorities said on Thursday.

The platform will consist of a geographic information system, remote sensing satellite and video surveillance system to supervise the waters, said Wang Yiping, director of the Cultural Relic Bureau of South China's Hainan province.

"This platform is intended to help us better protect underwater cultural relics," said Wang.

According to Wang, special underwater preservation zones will also be designated in areas where cultural relics are prone to be stolen.

The Xisha Islands consist of a cluster of about 40 islets, sandbanks and reefs. During ancient times, many Chinese merchant ships struck the reefs and sank while sailing to southeast Asia, India and the Middle East, leaving abundant treasures and cultural relics in the sea.

A total of 124 historic underwater sites have been found in the South China Sea so far.

An examination of some of the sites in 2011 showed that 26 of 48 examined sites had been damaged by thieves.

The Tanmen police station in east Hainan, which is responsible for both rescuing fishing ships and cracking down on the illegal salvage of cultural relics, has saved over 2,000 antiques to date, said Zhu Liming, head of the police station.

However, the antiques that have been unearthed and brought back to the mainland only account for a small share of the underwater relics.