A Tunisian activist who sparked controversy by posting topless pictures of herself online in support of Arab women's rights vowed on Monday to bare her breasts in protest, after being held captive by her family and beaten.

The young woman, Amina Tyler, was speaking on Skype to Ukrainian women's power group Femen after running away from home, where she said she was abducted, drugged and beaten by members of her family.

"I don't want to leave Tunisia before doing a topless protest. I will do a topless protest then I will leave," she said in the video posted on Femen's Facebook page.

Tyler described being grabbed by a cousin from a cafe in Tunis, forced into a car and taken first to her aunt's house and then to her grandmother's house, where she was subjected to a virginity test and made to read the Koran.

She said she was given "strong doses of medicine" to send her to sleep and make her docile.

The Tunisian activist provoked the ire of Islamists when she posted pictures of herself online last month with the words "My body belongs to me, it doesn't represent anyone's honour," and "F*** your morals" emblazoned across her bare breasts.

After posting the pictures, Tyler told French television that she feared for her life and wanted to leave Tunisia, adding that she had been forced to stay at home, in a town outside Tunis, where she had been beaten.

Earlier on Monday, her mother confirmed that Tyler had left the family house three days earlier but denied that she had been kidnapped, saying that her family was simply trying to protect her.

"Some groups are exploiting my daughter's story at her expense," Tyler's mother, who refused to be identified, told AFP, her voice choking with emotion.

"There has never been any kidnapping. We are just trying to protect our daughter by refusing to let her go out on her own for the sake of her security," she said, adding that she feared for the young woman.

Tyler risks six months in prison for breaching the peace.

Her actions were a defiant imitation of women's topless protest group Femen, in a country where hardline Muslims have become increasingly active since the January 2011 revolution.

The Femen movement has flourished since 2010, with feminists around the world stripping off in protest against issues ranging from homophobia to prostitution and sexism.

Tunisian women are some of the most free in the Arab world but have limited inheritance rights, which women's groups say have been further abused by the ruling Islamist party Ennahda.