The Philippines is reporting erratic movement for the largest of China's coast guard vessels. The ship was spotted about 77 nautical miles off the north-western province of Zambales. Manila has warned of the impact on local fishermen.

The Philippines accused China on Tuesday of intimidating its fishermen at a disputed South China Sea shoal, and normalising an "illegal presence", after Beijing sent its largest coast guard vessel into Manila's maritime zone.

The Philippines said Tuesday it was alarmed by Chinese coast guard patrols which are growing closer to the country's shore.

The Philippines said China's deployment of its largest coast guard vessel inside Manila's exclusive economic zone (EEZ) was alarming and clearly meant to intimidate fishermen operating around a contested shoal in the South China Sea.

The Philippines has lodged a diplomatic protest over the presence of Chinese coast guard vessels, including a “monster ship”, in its claimed exclusive economic zone, amid fears that Beijing wants to alter the status quo in the South China Sea.

China’s largest coast guard vessel, nicknamed “The Monster,” returned to the West Philippine Sea over the weekend, according to the Philippine Coast Guard (PCG). The PCG accused Beijing of trying to “normalize” such deployments to change the current situation in the area.