President Benigno Aquino III has renamed western offshore waters the West Philippine Sea to define his country's territory while disputing overlapping claims made by Beijing and others.

Officials said Wednesday that Aquino's order, which took effect after being signed on Sept. 5, called on the government's map-making agency to use the new name to label waters west of the Philippine archipelago, including those around the disputed Spratly Islands and the Scarborough Shoal.

The potentially oil- and gas-rich Spratlys are contested by China, the Philippines and four other Southeast Asian claimants. China and the Philippines figured in a maritime standoff over the Scarborough Shoal in April.

Aquino said rival claimants use different names for areas they claim and the new name will help define Manila's territorial claims.

Aquino's order was expected to draw protests from China, which has opposed past Philippine attempts to assert sovereignty over islands and waters both countries dispute. Their renewed spats have strained ties.

A planned meeting between Aquino and China's leader Hu Jintao failed to take place on the sidelines of an annual summit of Pacific Rim countries in Vladivostok last week, but the Philippine leader expressed hope they would meet in the near future.

"I'm still hoping we can have a dialogue and have a heart-to-heart talk ... in total honesty and openness," Aquino told reporters. "That seems to be the way forward to settle all of these things."