A large group of rare Phayre's leaf monkeys has been spotted in southwest China, an animal expert said.

More than 200 of the leaf monkeys, a Class I state-protected wild animal, were seen by volunteers in Yunnan's Dehong Dai and Jingpo earlier in January.

It was the biggest group ever spotted in China, Xinhua news agency reported. "A group of Phayre's langurs usually consists of no more than 30, so the latest discovery is really unusual," Chen Jianwei, with Beijing Forestry University said.

Phayre's leaf monkeys, also known as Phayre's langurs, scatter in western Yunnan and in eastern and northern Myanmar.

They usually live in forests which are upto 2,700 metres above sea level, said Chen.

Files compiled in the 1980s show less than 2,000 Phayre's langurs lived in Yunnan. By the end of the 20th century, logging had further reduced their habitat and their number.

Last year, a female albino Francois' leaf monkey was spotted in a national reserve in south China's Guangxi Zhuang Autonomous Region, according to the management bureau of the reserve.

A total of 118 Francois' leaf monkeys, belonging to 17 different groups, have been found living in the reserve. There are fewer than 2,000 Francois' leaf monkeys worldwide. The International Union for the Conservation of Nature (IUCN) listed the animal as an endangered species in 2008.

Zhou Fang, a professor from the college of animal science and technology at Guangxi University, said albinism is a natural phenomenon caused by gene deletion, and it is rare to see an albino Francois' leaf monkey in the region.