The health authority of East China's Zhejiang province is investigating a kickback scandal at five major hospitals in the province revealed by an online post, local health officials said on Saturday.

More than 200 doctors in five well-known hospitals in the province's Hangzhou and Ningbo cities were accused on Thursday of taking kickbacks from Hangzhou Haijiang Pharmaceutical Technology Co Ltd, a pharmaceutical sales agency.

A netizen, who goes under the name of Xiaoyu and claims to be a former employee of the agency, published a post on a major Internet forum in Ningbo on Thursday, listing the doctors' names, their employee ID numbers, departments and the amounts they took in January.

A doctor in the neurology department in Ningbo No 2 Hospital was said to have accepted more than 30,000 yuan (US$4,563) in a month, the largest amount among the listed doctors.

According to the post, hospitals charge 104.2 yuan for one type of injection, which costs only 22 yuan to manufacture, while the doctor who prescribes it gets a commission of about 25 yuan.

Xiaoyu said that he or she exposed the case because the agency always delayed payment of his or her salary. However the head of the agency denied the claims to local media, saying that the online post was the result of commercial disputes and was done with malicious purpose.

An unidentified doctor, who was on the list, denied knowing the name of the agency or those of any of its employees when contacted by China Youth Daily.

However, a doctor from a class-A hospital in East China's Anhui province, who asked to be anonymous, told China Daily that it was quite common for the country's doctors to receive kickbacks provided by pharmaceutical agents.

He said that to increase the sales volume of a particular medicine, the agents usually first approached a hospital's department directors and the head of the medicine management department and then contacted the doctors, giving them different amount of cash kickbacks.

A doctor will prescribe the medicine with the higher kickback when two similar types of medicines perform the same function.

"I think the low salaries of doctors in China, which I can say don't match the effort they make, are the major cause of this phenomenon," he said, adding that the kickback a doctor accepts is usually greater than his salary.

"What's more, it's difficult for a doctor to refuse the kickback when all the other doctors accept it. It will alienate him or her from the others," he added.

Industry insiders said that the monthly salary of an ordinary doctor in Shanghai is about 5,000 yuan, but the kickbacks given by pharmaceutical agents can exceed 10,000 yuan each month.

"It is a regulation established by all hospitals that pharmaceutical agents are not allowed into hospitals, but it's just not the case in reality, as the agents usually have some connection with the senior executives at the hospitals," said Tang Jianli, a lawyer from Shanghai Haida Law Office, who is experienced in medical disputes.

He suggested the government stipulate suppliers of commonly used medicines stop pharmaceutical agents from providing kickbacks.

"The situation will hopefully be improved in the next two or three years with the deepening of the country's medical reform, which aims to increase doctors' incomes and lower the prices of commonly used medicines," he said.

A similar case happened in Hangzhou in November 2010 when a netizen published online a list of doctors and the kickbacks they accepted, which he retrieved from a flash disk he picked up. The doctors and the pharmaceutical sales agency mentioned in the post were punished after the provincial health department investigated the case.