UN human rights chief Navi Pillay on Friday called on China to address the many grievances in Tibetan areas that have led to a growing number of desperate protests, including self immolations.

"I recognise Tibetans' intense sense of frustration and despair which has led them to resort to such extreme means," the United Nations High Commissioner for Human Rights said in a statement, calling on Beijing "to recognise this, and permit Tibetans to express their feelings without fear of retribution."

Pillay said she was disturbed by "continuing allegations of violence against Tibetans seeking to exercise their fundamental human rights of freedom of expression, association and religion."

She lamented reports of "detentions and disappearances, of excessive use of force against peaceful demonstrators, and curbs on the cultural rights of Tibetans."

She mentioned the case of a 17-year-old girl who was reportedly beaten severely and sentenced to three years behind bars for handing out flyers calling for Tibetan freedom, and others sent to prison for up to seven years for writing essays, making films or distributing photos of events in Tibet outside China.

"I call on the government to respect the rights to peaceful assembly and expression, and to release all individuals detained for merely exercising these universal rights," Pillay said, adding that she had had several exchanges with Beijing about such issues.

She also urged Tibetans to find "other ways" than self-immolation to protest.

About 60 ethnic Tibetans, many of them monks and nuns, have set themselves on fire in China since February 2009 to protest against Beijing's rule in Tibet, with seven self-immolation protests reported last week alone.

Only a small minority are thought to have survived.

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.

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