The Philippines on Monday denied China had a "temporary special arrangement" with Manila to allow the delivery of supplies to Philippine troops occupying a disputed South China Sea reef, calling it "a figment of imagination".

Philippine Coast Guard flyby over the South China Sea.

The Chinese coastguard said on Saturday it had temporarily allowed the Philippines to provide food and water to soldiers stationed at the BRP Sierra Madre, a vessel grounded in 1999 at the Second Thomas Shoal, 190 km (118 miles) off Palawan province, to assert Manila's territorial claims.

"This is a figment of the imagination of the Chinese coastguard. There is no truth to this." National Security Council spokesperson Jonathan Malaya told state-run broadcaster PTV-4.

The Chinese coastguard said the Philippines air-dropped supplies to the navy vessel on Jan. 21. Malaya did not confirm nor deny the airdrop, but said supplying troops was his country's right.

"We do not need to get the permission of anyone, including the Chinese coastguard, when we bring supplies through whatever means, whether by ship or air," Malaya said.

The Philippines' occupation of the shoal has irked Beijing and has been a flashpoint in recent disputes between them, which have intensified under President Ferdinand Marcos Jr, who has sought stronger ties with the U.S. military.

China claims almost the entire South China Sea, a conduit for more than $3 trillion in annual ship commerce. Its territorial claims overlap with the exclusive economic zones of the Philippines, Vietnam, Indonesia, Malaysia and Brunei, some of which have competing claims to various islands and reefs.

In 2016, the Permanent Court of Arbitration in the Hague said China's claims had no legal basis, a decision Beijing has rejected.