Beijing claims the South China Sea in nearly its entirety, despite an international ruling that its assertion has no legal basis.

Under an executive order by Philippine President Ferdinand Marcos on Tuesday, Manila will rename more than 100 reefs, islands, atolls and other features belonging to the Spratly archipelago, the site of repeated confrontations between Philippine and Chinese vessels.

At a press briefing on Wednesday, China's foreign ministry spokeswoman Mao Ning said the move "infringes upon China's territorial sovereignty and violates the UN charter and relevant international laws".

"China firmly opposes the Philippines undermining China's sovereignty and rights and interests, and will take necessary measures to resolutely safeguard its territorial sovereignty and maritime rights and interests in the South China Sea," she said.

The Philippines and China, along with Brunei, Malaysia, Taiwan and Vietnam, have competing claims to areas of the South China Sea, most importantly the Spratlys, which are believed to sit on vast oil and gas resources.