Of the 70,000 new infections reported in 2005, 49.8 percent were contracted through sexual contact, the Ministry of Health and China's Centre for Disease Control and Prevention said in a joint report, according to the China Daily.
Th spread of the virus among drugs abusers through injections stood at 48.6 percent of the total, it said.
'It is the first time since 1989, when the first HIV infection was detected (in China), for sex to top the transmission list nationwide nationwide,' Gao Qi of the China HIV/AIDS Information Network was quoted as saying.
No figures were given for previous years, or for 2006, but the report said that drug abuse had been the dominant transmission route for the 650,000 Chinese people infected by HIV.
Gao was quoted as saying that the new trend would make it harder to control the spread of the deadly virus, now that the chief transmission route had gone beyond the drug-abusing population.
Efforts to curb the new trend were targeting China's burgeoning sex industry, the China Daily said, adding that the government had initiated a campaign to make sex workers force clients to use condoms, a drive inspired by the 100-percent condom use campaign in Thailand.