China's largest fishery administration vessel, China Yuzheng 311, arrives in the Xisha Islands March 17, 2009. The vessel will patrol the South China Sea.(Xinhua)

China's largest fishery administration vessel began patrolling the South China Sea Tuesday afternoon.

"China Yuzheng 311" will patrol the Xisha Islands such as Zhaoshu, Yongxing and the East Island to give Chinese fishermen in this area more powerful protection for their interests and safety, said Liu Guimao with the Administration of Fishery and Fishing Harbor Supervision for the South China Sea.

"Despite hot weather of nearly 30 degrees Celsius, the 311 crew was in good spirits and confident with their tasks," Liu told Xinhua.

"China Yuzheng 311" made a week-long voyage to the region from its home port in Guangzhou before arriving Tuesday noon. The vessel stopped at a naval base in Sanya in the southern Hainan Province last Thursday for supplies and set sail for the islands, which are about 180 nautical miles southeast of Hainan.

However, the vessel encountered a storm which delayed its arrival in the islands which was expected to be on Sunday, the vessel's captain, who preferred not to be named, told Xinhua.

With 112.68 meters in length, 15 meters in width, and a maximum displacement of 4,600 tonnes, the vessel is the largest of its kind in China.

Equipped with the Global Maritime Distress Safety System (GMDSS), an advanced communication system initiated by the International Maritime Organization (IMO), "China Yuzheng 311" can sail non-stop for 8,000 sea miles at a maximum speed of 22 knots. It was converted from a rescue vessel of Chinese navy

Wu Zhuang, director of the Administration of Fishery and Fishing Harbor Supervision for the South China Sea, said the vessel will escort Chinese ships around the islands where "fishing illegalities by neighboring countries are on the rise."

"China has indisputable sovereignty over the islands of the South China Sea and their adjacent waters," Foreign Ministry spokesman Qin Gang said Tuesday.

His comments came after he was asked to respond to accusations of China "flexing military might" by sending ships to the South China Sea.

"The vessel was heading there for a routine fishery administration mission," said Qin.

Editor: Yan