More than 50 Chinese militia vessels were seen lurking near disputed islands in the South China Sea.

Aerial footage shows clutches of Chinese ships sailing near Pag-asa Island or Thitu Island - the largest in the resource-rich Spratly archipelago - on February 20. The fleet was also accompanied by China Coast Guard vessel 5101.

Six more Chinese militia vessels were also spotted in the contested Rozul Reef area.

Philippine Coast Guard (PCG) spokesman Commodore Jay Tarriela said the Chinese ships were seen during a 'maritime domain awareness flight' of two planes belonging to the Philippine Bureau of Fisheries and Aquatic Resources (BFAR) over territorial waters.

He said in a statement: 'Throughout the flight, the BFAR aircraft consistently challenged the illegal presence of Chinese maritime forces encountered. This mission also documented the unlawful activities conducted by the Chinese Coast Guard and Maritime Militia in the Kalayaan Island Group.

'Undeterred by provocations from the People's Republic of China, BFAR and PCG remain resolute in maintaining our presence in the West Philippine Sea and confronting the illegal activities of foreign vessels.'

The Philippines' patrol flight was carried out after a Chinese navy helicopter flew dangerous close to a BFAR plane over the Scarborough Shoal just two days earlier.

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.