A Tibetan monk was beaten, tortured and imprisoned after his arrest in an area that has become a flashpoint for a wave of protests against Chinese rule, a press freedom group said on Thursday.

Yonten Gyatso, a senior monk and human rights activist in the restive Aba county, in China's southwestern Sichuan province, was sentenced to seven years in prison for spreading information about protests in Tibet, according to Reporters without Borders.

The monk was sentenced on June 18 by Aba Intermediate People's Court, but his family and the news organization that he contributes to only heard about it on Wednesday, the group said.

He is accused of sharing photographs and information about the self-immolation of Tenzin Wangmo, who last October became the first woman to set herself alight as part of the wave of protests, it added.

Yonten Gyatso was arrested at Khashi Gyephel Samtenling monastery in Aba County on October 18, before being taken to a detention centre in Chengdu, the Sichuan provincial capital, the group said.

The organisation claimed he was beaten and tortured by officers from the local State Secrets Bureau.

Nearly 50 ethnic Tibetans, many of them monks and nuns, have set themselves on fire in the local area to protest at what they say is religious repression.

Many Tibetans in China accuse the government of enacting religious repression and eroding their culture, as the country's majority Han ethnic group increasingly moves into historically Tibetan areas.

But China rejects this, saying Tibetans enjoy religious freedom and pointing to huge ongoing investment, which it says has brought modernisation and a better standard of living.

Calls made by AFP to Aba Intermediate People's Court went unanswered.