China has warned the Philippines not to abuse its goodwill arrangement that allows Filipinos to fish with small boats in designated waters near China's Huangyan Island in the South China Sea.

"If the Philippine side abuses China's goodwill, we will take countermeasures in accordance with the law," Foreign Ministry spokesman Wang Wenbin said at a regular news briefing on Wednesday in Beijing.

The remarks came as about 200 Filipinos on board five commercial fishing vessels sailed on Wednesday toward the island, over which, with its adjacent waters, China has indisputable sovereignty.

The trip was led by a group called Atin Ito (This is Ours), about two weeks after the China Coast Guard took necessary measures and expelled a Philippine Coast Guard vessel and another official vessel entering the waters of Huangyan Island without permission.

The China Coast Guard said on Wednesday that Philippine vessels illegally entered Chinese waters in the South China Sea, and it conducted normalized law enforcement activities in adjacent waters off Huangyan Island.

According to the goodwill arrangement made in 2016, fishing by Philippine fishers in designated areas off Huangyan Island is not an issue, but the arrangement requires that the Armed Forces of the Philippines, Philippine Coast Guard and other Philippine government vessels and aircraft refrain from entering the 12 nautical miles and corresponding airspace of the island.

However, the arrangement was unilaterally disrupted by the current Philippine administration who dispatched its coast guard ships and official vessels to intrude a number of times into waters within 12 nautical miles of Huangyan Island and encouraged Filipino fishers to challenge the arrangement to help promote its political agenda.

As the Chinese side has repeatedly said, the real cause of heightened tensions in the South China Sea over the past year is the Philippine administration's unilaterally abandoning previous agreement and understanding between the two sides.

"Huangyan Island has always been China's territory," Wang said. "If the Philippines infringes on China's territorial sovereignty and jurisdiction, China will defend its rights in accordance with the law. The relevant responsibilities and consequences are entirely borne by the Philippine side."