President Benigno Aquino said Wednesday that the Philippines had officially named South China Sea waters off the country's west coast the "West Philippine Sea", in a move that could further raise tensions with China.

Aquino said his government would register the new name with the United Nations as part of efforts to delineate its sovereign territory, even those areas claimed by China or others.

"This is to clarify which are the areas that we are claiming," Aquino told reporters.

China claims nearly all of the South China Sea, even waters approaching the coasts of other countries.

The Philippines, Vietnam, Malaysia, Brunei and Taiwan also have overlapping claims to the waters, making the area one of Asia's potential military flashpoints.

The Philippines has been locked in an increasingly bitter row with China this year over their competing claims.

Ships from both countries engaged in a stand-off at Scarborough Shoal, a tiny group of islands in the sea, in April, and the Philippines says Chinese vessels remain there.

The Philippines has also accused China of bullying diplomatic tactics.

An administrative order released by the presidential palace on Wednesday said the "West Philippine Sea" would be included in government maps and charts.

"In the exercise of sovereign jurisdiction, the Philippines has the inherent power and right to designate its maritime areas with appropriate nomenclature for purposes of the national mapping system," it said.

"The maritime areas on the western side of the Philippine archipelago are hereby named as the West Philippine Sea.

"These areas include the Luzon Sea as well as the waters around, within and adjacent to the Kalayaan Island Group, and Bajo De Masinloc, also known as Scarborough Shoal."

Kalayaan is the Philippine government term for the areas it claims in the Spratly Islands, one of the most hotly contested archipelagos in the sea.

The Philippines has a military garrison on one of the Spratly islands. It also includes Mischief Reef, which China occupied in 1995.

The Philippine government has been referring to the South China Sea as the "West Philippine Sea" since last year, but this is the first time it has made it official with plans to inform the United Nations.

The Chinese embassy spokesman could not be contacted for comment.