About 70% of prostitutes have been abused by the police, according to a report released in Johannesburg yesterday.

"The human rights abuse of sex workers in South Africa is alarming and demands immediate attention," the Sex Workers' Education and Advocacy Taskforce said.

"Sex workers experience violence during their arrest by the police, who routinely beat them, pepper-spray them and sexually assault them."

The report was based on interviews with 308 prostitutes, most of them in Cape Town, by the Women's Legal Centre. Most of the sex workers were women but the respondents included men and transgender people.

The report included first-person narratives by people who recounted being forced to perform oral sex or being gang-raped by police officers. They said that police officers often assaulted them.

The study found that police officers did not identify themselves or wear name tags when committing the offences.

"Police officers commit these crimes with impunity. They remove their name tags so that sex workers are unable to identify them and they instil such fear in the sex workers that they are afraid to report these crimes to the authorities," the report said.

Arbitrary arrest was still common despite a 2009 order by the Cape Town High Court that police could not arrest sex workers unless they intended to prosecute them.

About 138 prostitutes said they had been arrested but only 21 had appeared in court. Most of those arrested were fined.

Western Cape police spokesman Captain Frederick van Wyk said the allegations of police abuse had not been reported to the police.