The number of women and girls in Afghanistan imprisoned for "moral crimes" has risen by 50% in the past 18 months, a rights group says.
Human Rights Watch says many are jailed for running away from home, often from forced marriages or domestic violence.
Others are behind bars as a result of alleged adultery, in truth often involving rape, it said.
The government should "get tough on abusers of women and stop blaming women who are crime victims", said HRW.
It said 600 women and girls were now imprisoned for "moral crimes" - the highest since the US-led overthrow of the Taliban 12 years ago.
About 110 of those were girls under 18.
Human Rights Watch's alert comes just three days after angry scenes in the Afghan parliament forced a halt to a debate about reinforcing a law to prevent violence against women.
The law banning violence against women, child marriages and forced marriages was passed by presidential decree in 2009, but did not gain MPs' approval.
Some women's activists had worried that by opening up the law for debate, it might be watered down or even repealed.
Human Rights Watch says many of the protections within the Elimination of Violence Against Women law - which bans forced and underage marriage, beatings and rape - are still not being implemented on the ground.
"Four years after the adoption of a law on violence against women and 12 years after Taliban rule, women are still imprisoned for being victims of forced marriage, domestic violence, and rape," Brad Adams, HRW Asia director, was quoted as saying.
It said many of those detained for so-called moral crimes had attempted to report rapes to police only to be arrested for adultery, while others fleeing forced marriages or abuse were jailed for running away from home - even though that is not a crime according to the Afghan criminal code.
And it said that many of those accused of "moral crimes" were subjected to "virginity tests" with no medical basis which contravened international law.
"Coerced 'virginity' examinations are a form of sexual assault," Mr Adams said. "Afghan police, without any scientific basis, are routinely forcing these unspeakable examinations on women and girls."
One prisoner, Sorya, told HRW she was forced to marry at 12 and was abused by her husband. After nine years of marriage during which she had three children, he accused her of running away with another man whom she had not even met.
HRW said Sorya was serving a sentence of five-and-a-half years in prison. She was pregnant at the time of her arrest, and her baby died in prison three weeks after he was born.
HRW's Afghanistan researcher, Heather Barr, said the dramatic increase in prosecutions for "moral crimes" could be related to increased confidence among religious conservatives as international troops prepare to leave Afghanistan in 2014.
"I think it's possible that as everyone anticipates the departure of foreigners, there is a feeling that in a sense things can go back to normal, and... people will be free to ignore [women's rights] in the future,'' Ms Barr told AP news agency.
"If that's true, that's really is a tragedy, because these ideas didn't come from foreigners. These ideas came from Afghan women's rights activists,'' she said.
HRW called on Afghan President Hamid Karzai to issue a decree that running away should not be treated as a crime and instruct police to investigate possible incidents of violence against women.
It urged international donors to pressure the government to improve women's protections.
The Afghan interior ministry says it is preparing a response to Human Rights Watch's report.