The Chinese Coast Guard appeared to cut off Philippine ships travelling to a contested atoll during a resupply mission in the South China Sea on Wednesday.

Footage shows a Chinese Coast Guard vessel with bow number 21551 seemingly blocking a Philippine Coast Guard (PCG) ship escorting supply boats entering the Ayungin Shoal area on October 4.

The PCG ships were taking supplies to the BRP Sierra Madre, a World War II-era vessel intentionally grounded by the Philippines to lay claim to the shoal back in 1999.

The PCG said the resupply mission was successful despite the CCG's 'dangerous manoeuvre'.

The incident comes amid mountain tensions over sovereignty and fishing rights in the disputed region.

In early August, the CCG had blasted Philippine ships with water cannons in the same area. While in September, the CCG reportedly hounded Philippine government vessels several times, chasing them away and blocking them from entering disputed waters.

The CCG had also installed floating buoy barriers, which have been dismantled by the PCG, to keep Filipino fishermen away.

Communist China currently lays claim over almost the entire South China Sea, one of the world's busiest sea lanes. But a United Nations-backed tribunal in 2016 deemed its claims groundless.