Sex workers in China risk tough punishment, but that has failed to reduce the number of people engaged in the trade.
Under Chinese law, sex workers and their clients are subject to 10 to 15 days in short-term detention.
They can be fined up to 5,000 yuan (S$1,030) and sentenced to between six months and two years in a "custody and education" centre without a court hearing or the right to defend themselves.
Detainees are typically forced to do jobs such as cutting rubber strips for tyres, making cloth toys, folding paper bags or wrapping disposable chopsticks for as long as nine hours a day, said Asia Catalyst, a New York-based rights group, in a recent report.
The cost of detention must be met by inmates or their families and it ranges from 5,000 to 10,000 yuan for a minimum six-month term. The group based its report on interviews with 30 former inmates, AFP reported.
"Custody and education" centres were established in the early 1990s and are managed by the country's public security authorities rather than by the Justice Ministry.
Said Asia Catalyst: "The harsh punishment China metes out to sex workers fails to eradicate or decrease the number of persons engaged in this trade, while further infringing on their human rights.
Prostitution is illegal in the Chinese mainland, but it is thought that there are 2.7 million to six million sex workers, operating from places including karaoke bars, hair salons, saunas and massage parlours.
As many as 28,000 are detained and held each year.
The group said that despite the "custody and education" system's goal of providing detainees with the skills to pursue new avenues of employment, all the sex workers it had interviewed returned to the sex industry immediately after their release.
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