Pornography in China is illegal, and conservative social attitudes towards women remain the norm, often reinforced by state media and popular culture.

It comes after a Chinese university expelled a female student this month for "damaging national dignity" over videos posted by a Ukrainian esports player on Telegram suggesting they had been intimate.

The Chinese state-owned Southern Daily reported this week a woman had discovered that photos of her taken unknowingly had been shared in a Telegram forum with over 100,000 users, mostly Chinese men.

Members of the forum also shared photos of their girlfriends, ex-girlfriends and wives, according to a commentary in the Guangming Daily, an outlet backed by China's ruling communist party.

Revelations of the group have sparked widespread outcry online.

"We are not...'content' that can be randomly uploaded, viewed and fantasised about," read one comment on Instagram-like Red Note.

"We can no longer remain silent. Because next could be me, or it could be you."

A related hashtag has been viewed more than 230 million times on social media platform Weibo since Thursday.

The largest group, called "Mask Park", has since been taken down, but smaller spinoffs remain active, according to women contacted by Southern Daily.

Telegram encrypts its users' messages and is banned in China, but it is accessible using a virtual private network.

AFP has contacted Telegram for comment.

- 'Nightmares for life' -

The incident has drawn comparisons to a case in South Korea dubbed "Nth Room", in which a man blackmailed dozens of women into taking sexually explicit videos and sold them on Telegram.

Chinese women have taken to social media to detail their own experiences being filmed and photographed by men in public.

"What criminals consider 'regular' for them may be nightmares that countless women can't escape for the rest of their lives," one woman said, sharing an encounter on Douyin.

Chinese police have cracked down on illegal filming, arresting hundreds of people in 2022 over clandestine surveillance activities.

But women's rights are sensitive territory in China -- over the last decade, authorities have suppressed almost every form of independent feminist activism.

#MeToo activist Sophia Huang Xueqin was sentenced to five years in prison on charges of "inciting subversion of state power" after she became a symbol of the country's stalled feminist movement.

Chinese authorities have yet to publicly announce any action against the Telegram group.

But the Guangming Daily commentary urged "accountability" for the organisers of the Telegram group, and empathy for the people filmed.

Improving law enforcement would "enhance the overall sense of security, free women from the fear of being spied on and make privacy boundaries a truly untouchable red line", it said.