A big fleet of Chinese fishing vessels arrived at the disputed Spratly Islands in the South China Sea on Sunday, state media said, amid tensions with its neighbours over rival claims to the area.

The fleet of 30 fishing vessels arrived near the Yongshu Reef in the afternoon after setting off on Thursday from the Chinese province of Hainan, the official Xinhua news agency reported.

Chinese fishing boats regularly travel to the Spratlys, a potentially oil-rich archipelago which China claims as part of its territory on historical grounds.

But the fleet is the largest ever launched from the province, according to the report.

It includes a 3,000-tonne supply ship, and a patrol vessel has also travelled to the area to provide protection, the report said. The vessels will spend the next five to 10 days fishing in the area, it added.

The fleet's arrival came after China earlier Sunday extricated a naval frigate that got stranded four days earlier on a shoal in the Spratlys, near the western Philippine island of Palawan.

However the Philippines did not lodge a diplomatic protest over the matter, saying the stranding of the vessel in its exclusive economic zone was likely an accident.

China says it has sovereign rights to all the South China Sea, believed to sit atop vast oil and gas deposits, including areas close to the coastlines of other countries and hundreds of kilometres (miles) from its own landmass.

But Taiwan, Vietnam, Brunei, Malaysia, and the Philippines also claim parts of the South China Sea.

The Spratlys are one of the biggest island chains in the area.

The rival claims have long made the South China Sea one of Asia's potential military flashpoints, and tensions have escalated over the past year.

The Philippines and Vietnam have complained that China is becoming increasingly aggressive in its actions in the area -- such as harassing fishermen -- and also through bullying diplomatic tactics.

The Philippines said the latest example of this was at annual Southeast Asian talks in Cambodia that ended on Friday in failure because of the South China Sea issue.

The Philippines had wanted its fellow Association of Southeast Asian Nations to refer in a communique to a standoff last month with China over a rocky outcrop known as the Scarborough Shoal in the South China Sea.

But Cambodia, the summit's host and China's ally, blocked the move.