Four Chinese vessels were found lurking in disputed waters, the Philippine Coast Guard (PCG) said on Tuesday.

PCG spokesman Commodore Jay Tarriela said at least four China Coast Guard (CCG) ships were found through Dark Vessel Detection sailing around the vicinity of the contested Bajo de Masinloc or Scarborough Shoal area of the South China Sea.

Footage shows crew of the PCG's BRP Teresa Magbanua - the largest in its arsenal - trading radio challenges with CCG vessel 3304 some 88 nautical miles from the Philippine shoreline on January 28.

In a statement, the PCG spokesman said: 'In addition, data from Dark Vessel Detection reveals the presence of three other Chinese Coast Guard vessels in the vicinity of Bajo De Masinloc. These include CCG-5901, approximately 99.37 nautical miles from Zambales; CCG-3502 at 131.70 nautical miles; and CCG-3103 at 133.97 nautical miles.'

The China Coast Guard has been sending ships near the coast of the Philippines since early January, with alarmed Philippine officials calling the maritime patrols 'illegal' and 'provocative'.

Among them is the massive CCG 5901, the world's largest coast guard vessel at 541 feet and 12,000 tons, which started lurking off the seaside province of Zambales on January 4 afternoon.

Authorities believe the ships were deployed to intimidate Filipino fishermen from entering the Scarborough Shoal, a disputed fishing ground and resource-rich area in the South China Sea.

Expansionist 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.

The Communist rogue state - accused of genocide for its crimes against the Uyghur population - has been steadily increasing its influence in recent years through investment in developing countries.