China expressed opposition on Tuesday to a Philippine maritime bill that aims at legalizing its claims and actions in the South China Sea, urging Manila to stop unilateral moves that would expand disputes and complicate the situation at sea.

Foreign Ministry spokeswoman Mao Ning said at a daily news conference that China has made serious demarches to the Philippines over the passing of the so-called Maritime Zones Act by the Philippine Senate, which she said attempts to enhance the illegal South China Sea Arbitration Award through domestic legislation and incorporate China's Huangyan Island and most of the islands and reefs in the Nansha Islands.

The move violated China's territorial sovereignty and maritime interests, she said.

Mao said the territory of the Philippines is defined by a series of international treaties, which never include Huangyan Island or any islands and reefs in the Nansha Islands.

She blasted the Philippines for illegally occupying islands and reefs in Nansha and going beyond its territorial limits to set the so-called Kalayaan Island Group, saying the moves are illegal and void.

Noting that territorial sovereignty is the premise and foundation of maritime rights and interests, Mao said the bill violates the United Nations Charter and the UN Convention on the Law of the Sea, as well as the spirit of the Declaration on the Conduct of Parties in the South China Sea.

Calling it an "egregious legislation", the spokeswoman said the act will irreversibly complicate the situation in the South China Sea.

She also reiterated that China's territorial sovereignty and maritime rights and interests in the South China Sea will not be affected by the South China Sea Arbitration Award under any circumstances.

Beijing urges Manila to return to the right track of addressing differences through negotiation and consultation, and work with China to safeguard the overall bilateral relations, as well as peace and stability in the South China Sea, she said.

Mao's remarks also came after China's Coast Guard took control measures in accordance with the law on Tuesday against Philippine vessels that illegally intruded into the waters near Ren'ai Reef in the Nansha Islands.

According to the CCG, two supply vessels and two Coast Guard vessels of the Philippines intruded into the adjacent waters of Ren'ai Reef, trying to transport supplies, including construction materials, to the military vessel illegally grounded at the reef.

The CCG said the actions were professional, restrained, justified and lawful.

"We once again urge the Philippines to stop its infringements and provocations at sea," Mao said.