The Philippines said Tuesday it had protested to China at the "illegal" presence of a Chinese warship and other vessels at a shoal occupied by Filipino marines in the South China Sea.

The stand-off is the latest in a growing dispute between the two countries over rival claims to parts of the sea. The Philippines said China occupied another Filipino-claimed shoal last year.

"We (have) filed with the Chinese embassy in Manila our protest on the provocative and illegal presence of Chinese government ships around Ayungin Shoal," said foreign affairs department spokesman Raul Hernandez.

Hernandez said three vessels -- one warship and two maritime surveillance vessels -- were still near the reefs and islets, also known as Second Thomas Shoal.

He said the protest was filed on May 10 and China had not responded. Hernandez would not say when the vessels were first detected.

Second Thomas Shoal is a tiny group of islets and reefs near the Spratly Islands chain, about 200 kilometres (120 miles) north of the Philippine island of Palawan.

It is very close to Mischief Reef, which the Philippines controlled until China built structures on it in the mid-1990s.

Philippine marines have been garrisoned at Second Thomas Shoal since the mid-1990s, said defence department spokesman Peter Galvez.

Neither he nor spokesmen for the navy, which has jurisdiction over the marines, would discuss with AFP details about the marine garrison.

The navy commander, Vice Admiral Jose Luis Alano, said the marines continue to be periodically resupplied without interference from the Chinese vessels.

"No navy ships are being harassed by them," Alano told reporters.

China insists it has sovereign rights to most of the South China Sea, which is believed to sit atop vast resources of oil and gas. It is also home to rich fishing grounds and shipping lanes vital to global trade.

The Philippines, Vietnam, Brunei, Malaysia and Taiwan also claim parts of the sea.

The Philippines and Vietnam have accused China of becoming increasingly aggressive in recent years in staking its claim.

The Philippines says China has since last year occupied another shoal to the north of the one currently in focus.