The Philippine coast guard said Monday it had found hundreds of frozen scaly anteaters, or pangolins, in the cargo hold of a Chinese boat that ran aground in a protected marine sanctuary last week.

Wildlife officials have been informed of the surprising discovery, which could lead to more charges for the 12 Chinese men arrested on charges including poaching after their boat was stranded in Tubbataha Reef last week.

"We found 400 boxes containing anteaters aboard the vessel, and we are now determining where these came from," coast guard spokesman Lieutenant Commander Armand Balilo told AFP.

He could not say whether the pangolins were frozen alive, or had already been butchered as meat.

A protected species, pangolins are widely hunted in parts of Asia for their meat, skin and scales. In China, they are known as a delicacy and are purported to have medicinal qualities.

According to the International Union of Conservation of Nature, all eight species of the insect-eating mammals are protected by international laws around the world.

Two -- the Malaysian and Chinese pangolins -- are in its "red list" of endangered species.

Pangolins are also found roaming in the wild in the western Philippine island of Palawan, the nearest land area to Tubbataha Reef where the Chinese boat had been marooned.

Balilo said the vessel remained stuck in Tubbataha, while the coast guard awaited arrival of a salvage ship to tow it it away.

Prosecutors charged the 12 Chinese fishermen last week with illegal poaching and with corruption for attempting to bribe Filipinos officials, and if convicted they could face long jail terms.

It was not immediately clear however what additional charges, if any, are to be filed against them with the discovery of the pangolins, Balilo said.

The grounding of the 48-metre (157-foot) boat came amid deep tensions between the Philippines and China over competing territorial claims to the neighbouring South China Sea.

China claims virtually all of the South China Sea on historical grounds, including waters close to the shores of its neighbours.

The Philippines, as well as Vietnam, have accused China of bullying other claimants as it aggressively stakes out its claims.