The incident occurred near Scarborough Shoal, a flashpoint between Manila and Beijing, which claims almost the entire waterway.
The National Task Force for the West Philippine Sea said in a statement that “Chinese coast guard ships utilised water cannons to obstruct” government vessels from delivering fuel and food supplies to fishing boats.
The multi-agency task force said it “vehemently condemns the illegal and aggressive actions carried out by the Chinese coast guard and Chinese maritime militia”.
But Chinese state television said the country’s coast guard had used “control measures in accordance with the law” against the Philippine vessels that had “intruded” into waters around the shoal.
China snatched control of Scarborough Shoal from the Philippines in 2012.
Since then, Beijing has deployed patrol boats that Manila says harass Philippine vessels and prevent Filipino fishermen from reaching the lagoon, where fish are more plentiful.
Scarborough Shoal is 240km west of the Philippines’ main island of Luzon and nearly 900km from the nearest major Chinese land mass of Hainan.
Under the 1982 United Nations Convention on the Law of the Sea, which China helped negotiate, countries have jurisdiction over the natural resources within about 370km of their shore.
Videos released by the Philippine coast guard showed China coast guard ships shooting water cannons at Philippine Bureau of Fisheries and Aquatic Resources (BFAR) vessels and hitting them with powerful blasts of water.
One boat’s communication and navigation equipment sustained “significant damage”, the task force statement said.
Aerial surveillance by the BFAR also showed a floating barrier had been reinstalled across the entrance to the shoal and was being guarded by Chinese boats, the Philippine coast guard said.
Filipino fishermen reported that the China coast guard installed the barrier earlier today, the task force said.
The Philippines and China have a long history of maritime incidents in the contested South China Sea, through which trillions of dollars of trade pass annually.
That is despite the Hague-based Permanent Court of Arbitration ruling in 2016 that China’s claims over the waters have no legal basis and its construction of artificial islands in disputed waters was illegal.
Beijing refused to take part in the proceedings and has ignored the judgment.
Vietnam, Malaysia, Brunei, and Taiwan also have claims to the sea.