The incident occurred near the contested Scarborough Shoal as the Philippine coast guard escorted boats distributing aid to fishermen in the area, spokesman Commodore Jay Tarriela said in a statement.

Video released by Manila showed a China Coast Guard ship and a much larger vessel bearing the number 164 on its hull colliding with a loud crash.

"The (China Coast Guard vessel) CCG 3104, which was chasing the (Filipino coast guard vessel) BRP Suluan at high speed, performed a risky manoeuvre from the (Philippine) vessel's starboard quarter, leading to the impact with the PLA (People's Liberation Army) Navy warship," Tarriela said.

"This resulted in substantial damage to the CCG vessel's forecastle, rendering it unseaworthy," he said.

The Chinese embassy in Manila did not immediately respond to a request for comment.

The reported collision is the latest in a series of confrontations between China and the Philippines in the South China Sea, which Beijing claims almost entirely despite an international ruling that the assertion has no legal basis.

More than 60 percent of global maritime trade passes through the disputed waterway.

The Scarborough Shoal -- a triangular chain of reefs and rocks -- has been a flashpoint between the countries since China seized it from the Philippines in 2012.

It was unclear if anyone was hurt in Monday's incident.

Tarriela told AFP the Chinese crew "never responded" to the Filipino ship's offer of assistance.

Earlier in the confrontation, the BRP Suluan was "targeted with a water cannon" by the Chinese but "successfully" evaded it, Tarriela's statement said.