The Beijing Public Security Bureau is cracking down on the illegal sale of medical booking registration numbers at 17 public hospitals. Those found dealing in the registration numbers will be held in custody and criminal charges might be brought in some cases.

"The action will continue until the illegal selling has stopped," said Cao Dongxiang, an officer at the bureau.

"As well as any punishments imposed, we will make a blacklist, if an offender is caught again they will face severe penalties."

The crackdown was launched on Monday.

Cao explained that the dealers earn money by buying registration numbers at the hospitals in the early morning and then selling them on to genuine patients at a higher price.

A registration number for a chief physician, for instance, sells for 14 yuan at a hospital, but the dealers charge patients 100 to 400 yuan, and for the most sought-after doctors, might demand 1,000 yuan.

Police in the city caught around 200 dealers in July, of which seven were in police custody.

Cao said that in summer many patients from other cities pour into Beijing seeking better medical treatment, creating more opportunities for those dealing in registration numbers.

Most registration numbers are for doctors with good reputations, who are in high demand.

A security guard surnamed Su at the China-Japan Friendship Hospital, who began working at the hospital last week, said he was told to pay special attention to the dealers on his first day.

"If we notice any dealer in the hospital, we are asked to call the director of the security department immediately," he said.

The Beijing Health Bureau promoted a booking system in all three levels of the city's hospitals since September last year.

However, statistics from the bureau show that only 13 percent of all registration numbers are available for booking and some famous doctors don't provide a booking service.

"There are always so many patients desperate to see famous doctors. No illegal selling means no other choices for those who want to see them," said a 60-year-old patient surnamed Hu living in Huilongguan, Changping district.

"For those people living far away from downtown, like me, it's long odds to buy a registration number of a chief physician, even by lining up outside the hospital. You have to wait at 4 am and are still not sure whether you could get registered or not," she said.

Guo Jiyong, an official at the Health Bureau said that the medical resources in the city were improving and that the government was working hard to build better residential clinics in order to release the pressure on big hospitals.

Li Jiaobao contributed to the story.