The Philippines said Sunday it had protested to Beijing over fresh alleged incursions by a Chinese navy ship and two other vessels into its waters last month.

The Department of Foreign Affairs (DFA) said it conveyed the Philippines' "serious concerns" to the Chinese embassy in Manila last week over recent actions in the South China Sea, which Manila calls the West Philippine Sea.

"The DFA protested the recent sightings of two Chinese vessels and a People's Liberation Army Navy ship at the vicinity of Escoda Shoal in the West Philippine Sea on December 11 and 12, respectively," it said in a statement.

Escoda, also called Sabina Shoal, is about 113 kilometres (70 miles) off the western Philippine island of Palawan and is well within the country's internationally recognised 200-mile exclusive economic zone.

But China claims all of the South China Sea, including the potentially oil-rich Spratly islands that also include Sabina Shoal.

China's rival Taiwan, as well as Brunei, the Philippines, Malaysia and Vietnam, also lay claim to all or part of the Spratlys, which experts have warned could be a flash point for potential armed conflict in the region.

Tensions in the decades-old dispute escalated last year amid accusations from the Philippines and Vietnam that Beijing was becoming increasingly aggressive in staking its claims in the area.

The Philippines tried to form a united front with its fellow Southeast Asian countries against China during a summit in Indonesia in November, but the proposal was coolly received by governments apparently wary of confronting the Beijing.

Chinese embassy officials were not immediately available to comment Sunday.