The province anks eighth in China in reported HIV/AIDS cases, with a total of 4,379 cases by June 30, Xinhua said, citing Chen Xiaochun, deputy director of the provincial health department.

Sexual transmission was responsible for 38 percent of cases reported in Hunan in the first half of this year, up from 31 percent in 2006 and 10 to 15 percent in previous years, the department's data showed.

Experts estimate the actual number of the province's HIV/AIDS cases may be 20,000 to 30,000, Xinhua said.

"The main cause of the increase of sexually-transmitted HIV cases is the increase in the number of migrant workers who have contracted the disease via sex," Chen Xi of the provincial disease prevention and control centre was cited as saying.

Nearly 58 percent of the reported HIV infections in Hunan were caused by drug users sharing needles, Xinhua said.

China had 183,733 officially reported HIV/AIDS cases in 2006, but experts estimated there were more likely 650,000 people living with HIV/AIDS in China.

During the annual legislative meeting in March this year, Shanghai delegate Li Dingguo, a doctor at the prestigious Jiaotong University Hospital, proposed mandatory AIDS testing at the city's clinics and hospitals.

Widespread stigma made patients reluctant to reveal their status, increasing the risk of transmission to doctors, nurses and other patients, he said.