SHANGHAI -- A Shanghai official has pledged to reform the medical industry following a scandal over doctors taking kickbacks.

Shanghai vice mayor Weng Tiehui said Monday that strict investigation, severe punishment and enhanced supervision will not help eradicate the problem at its root.

"Bribery is a recurring illness in the industry, and we need to deepen reform in the medical sector," Weng said.

Three doctors in Shanghai and one in Central China's Hunan province have been suspended pending investigation over kickbacks they allegedly took from pharmaceutical firms.

In an investigative report that aired on Saturday, China Central Television showed pharmaceutical sales representatives paying sweeteners to doctors at six hospitals in Shanghai and Hunan Province.

The report said the bribes amounted to 30 to 40 percent of the sales price of the drugs.

Anti-graft authorities in Shanghai are investigating the case. Authorities in Hunan promised to improve supervision of pharmaceutical sales in the interest of patients.

The National Health and Family Planning Commission has sent teams to Shanghai and Hunan to investigate.

Shanghai is trying to break the chain of interests between medical staff and pharmaceutical firms, Weng said.

"Shanghai will not tolerate or cover the behavior (of doctors receiving kickbacks)," Weng said.

The economic hub will launch a half-year-long crackdown following the scandal, said Wu Jinglei, director of the Shanghai Municipal Commission of Health and Family Planning.