A recent report that questioned the police's power to arrest and detain people involved in prostitution has revived the debate on the legalization of the centuries-old trade.

Experts said that despite calls to legalize prostitution, public opinion is still broadly against such a change.

The Beijing Academy of Social Sciences and the Social Sciences Academic Press published a blue paper on Wednesday, which said that the way police deal with sex workers and their clients "remains problematic, which urgently needs to be reformed."

The blue paper called for a change in the system to allow courts to administer appropriate penalties to those involved in the sex trade instead, to avoid the abuse of State powers and better protect citizens' personal freedom, news portal yicai.com reported Thursday.

Under the current system, police have the power to arrest people involved in prostitution or those who pay for sex, charge fines and detain them for up to two years without trial.

There are two ways to deal with sex workers and their customers in China, which are administrative detention and detention with education, according to relevant regulations.

"The so-called administrative detention and detention with education administered by police for sex-related violations are a violation of personal freedom which lack a legal basis, as well as unified standards," Wang Shuo, a lecturer from the School of Arts and Law under Beijing University of Chemical Technology, who is the author of the report, told the Global Times on Thursday.

"In the punishment process, the police play the role of both administration and judiciary," he said.

The recent controversial death of Lei Yang during a police raid on a foot massage parlor in Beijing suspected of involvement in the sex trade triggered a public outcry amid suspicions of police brutality and abuse of official power.

Police said Lei suddenly fell ill and died after he resisted arrest and attempted to escape.

"Some police use their power to collect unreasonable fines or use the specter of a damaged reputation to blackmail people who are involved in prostitution," Ke Qianting, an associate professor of gender studies at Sun Yat-sen University, told the Global Times on Thursday.

A policeman and four fellow auxiliary police officers from a police substation in North China's Shijiazhuang, Hebei Province were convicted of crimes for patronizing prostitution, robbery and blackmail on Tuesday.

A local court sentenced them to imprisonment from 10 months to up to eight years and fined up to 25,000 yuan ($3,800), news portal caixin.com reported on Thursday.

Against traditional morals

According to the blue paper, some legal workers and researchers support legalizing prostitution, and believe it is not necessary to punish sex workers or their clients.

But it also said that legalizing prostitution is unrealistic as it goes against public opinion. The majority are still influenced by traditional ethical and moral values, it said.

Pan Suiming, a sexologist from the Renmin University of China who studied the industry for decades, agrees that in the current social system, it will not be possible to take steps to legalize the sex trade, though the discussion on this issue has been going on for years, and many have shown sympathy toward sex workers.

In Beijing for example, the huge numbers of migrant workers come together with huge sexual needs, which, if not relieved, might cause security problems, Wang said, referring to the possible rise in rape crimes.

According to the blue paper, Beijing, together with nearby Tianjin municipality and Hebei Province, are the main migrant destinations. The number of the migrant population amounted to 14 million in the region by early 2015, the Beijing government stated on its website.

"More people now see the sex trade as fulfilling a physical need, instead of a moral issue with a seedy reputation," Ke said.

The legalization of prostitution might benefit public health and public security, as sex workers could openly access medical care and undergo regular examinations and authorities can better supervise them, Ke said.