The United Nations said it was concerned by high levels of ignorance and stigma towards HIV/AIDS in China, as it released the results of a survey of 6,000 people on Friday.

More than 48 per cent of respondents in six of China's major cities said they believed they could be infected with HIV through mosquito bites, while 83 per cent had never looked up information on HIV/AIDS and 30 per cent did not know how to use a condom, UNAIDS said in a report.

Nearly 65 per cent said they would not be willing to live with someone infected with HIV, 48 per cent said they were unwilling to eat with an HIV-infected person, and 41 per cent were unwilling to work with an HIV-infected person, the report said.

About 32 per cent of interviewees agreed that people with HIV/AIDS "deserved their disease because of their sexual behaviour or drug abuse," while 88 per cent of interviewees believed they were not at risk of HIV infection.

"These data are really a cause for concern," UNAIDS China coordinator Bernhard Schwartlaender said in a statement.

"We see that there are still many misconceptions around AIDS in the population, which contribute to stigma and discrimination," Schwartlaender said.

"But there are also worrying contradictions between knowledge and behaviour," he said.

"Though people know that HIV can be transmitted through unprotected sex, many still do not protect themselves with a condom when engaging in risk behaviour," he said.

About 11 per cent of interviewees said they had sex with someone who was not their regular partner in the previous six months, but 42 per cent of those respondents said they had not used condoms.

Only 19 per cent said they would use a condom if they had sex with a new partner, the report said.

The survey was carried out in Beijing, Shanghai, Shenzhen, Wuhan, Zhengzhou and Kunming among four social groups of mainly younger people.

"I am saddened by the level of stigma of people living with HIV, including in the work place," a UNAIDS press release quoted Michael Shiu, the director of the Global Business Coalition on HIV/AIDS, tuberculosis and malaria, as saying of the findings.

China's health ministry reported a rise of about 22 per cent in confirmed HIV infections last year, raising its estimated number of infections from 650,000 to 700,000.

Most HIV infections are believed to be still undiagnosed because of ignorance, fear, poverty and other factors.

Under pressure from the United Nations, which has long warned of a potential epidemic in China, the government has become more open about HIV/AIDS issues in recent years.

In its latest report in November, the health ministry warned that the spread of HIV/AIDS in China "continues to be driven by high-risk behaviour within particular sub-populations."

The ministry said sexual transmission had become the "main mode for the spread of HIV," with an estimated 45 per cent of new infections through heterosexual transmission last year.