At least six patrol vessels belonging to provincial units of the Maritime Safety Bureau of China were sent to the South China Sea in recent weeks, with several others being prepared for departure, China Daily reported.

Some of the busiest international shipping lines cut through the South China Sea, which is home to the disputed Spratly and Paracel islands that are valued for potentially vast mineral and oil deposits.

China announced last month that it had sent one civilian patrol vessel to waters around the Spratlys, drawing concern from the Philippines, one of the nations claiming sovereignty over the area.

Recently renewed claims by nations over parts of the Spratlys were one reason for China stepping up its presence in the area, China Daily also reported.

The increased patrols also come after a near collision last month between Chinese boats and a US naval surveillance ship in international waters within China's exclusive economic zone off Hainan Island.

"This year could be the starting point of many more disputes," the paper quoted Zhou Zhonghai, a maritime law specialist at China University of Politics and Law, as saying.

"Strategies with a firm stance to protect marine territories are of vital importance," Zhou was further quoted as saying.

He added that a United Nations effort this year to chart maritime territory had led to a rise in tensions, as nations hurry to submit claims and other legal documentations to the international body.

Apart from China and the Philippines, the Spratlys are claimed in whole or in part by Brunei, Malaysia, Taiwan and Vietnam.

Agence France Presse - April 18, 2009