China National Offshore Oil Corp (Cnooc), China's biggest offshore oil producer, late on Wednesday commenced its first unaided deepwater exploration in the South China Sea.

Cnooc's independent deep water oil drilling marks the beginning of a new era, as it typically relied on foreign partnerships such as the one established with Canadian Husky Energy.

The move to go solo comes amid increased tensions over ownership regarding disputed waters in the region and is perceived to be the Chinese's response to Philippine patrol ships around the area.

The part of the sea being drilled is known as the 43/11 block and reaches water depths of around 2,454 metres, making it the deepest in the South China Sea.