A Tibetan man has died after setting himself on fire at a Buddhist monastery in northwest China, the second self-immolation in the region in the last three days, rights groups said.

Dhondup, a Tibetan man in his 50s, set fire to himself at the Labrang monastery in western China's Gansu province, the London-based Free Tibet group said. Pictures posted by the group online appeared to show a body ablaze.

The man, who was married with an adopted son, died after the incident, US-based rights group the International Campaign for Tibet said, citing eyewitnesses.

"People confirmed that Dundrup is dead after the self-immolation," the group quoted Tibetan sources as saying.

Nearly 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, according to the group. A small minority are thought to have survived.

Monday's self-immolation followed another which occurred close to the same monastery on Saturday, when a man set himself alight and shouted slogans calling for the return of exiled spiritual leader the Dalai Lama, Free Tibet said.

Many of the previous self-immolation incidents have occurred in the more western province of Sichuan.

A spokesman for the Labrang monastery told AFP that he was "uncertain" whether the incident had occurred.

The Labrang monastery has been placed under "heavy restrictions" in recent months, Free Tibet said.

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.

The prime minister of Tibet's government-in-exile, Lobsang Sangay, has called on the international community to resist growing pressure from China and stand up for human rights in his homeland.