The survey of 12,000 youths aged between 15 and 25, who were interviewed by the reproduction health research unit of Johannesburg's respected Witswatersrand University, showed that one in 10 youths had contracted the virus that can lead to AIDS, South Africa's biggest killer.
Helen Reese, executive director of the unit, told AFP that young women were bearing the brunt of the epidemic.
"By the age of 19, 2.6 percent of males and 13.8 percent of females have HIV," she said.
By the age of 24, 11 percent of males are HIV-positive compared to 26.8 percent of females, Reese said, adding that many women were coerced into sex or "succumbed to subtle forms of coercion or presents, money or food."
Reese however said there were some signs of "cautious optimism," including the fact that the infection rate in the 15 to 19 age group appeared to be levelling off compared to other recent surveys.
"Another good factor is that condom use is now being reported by one-third against eight percent" cited in a 1998 health survey, she said.
"This is a good sign but in urban informal squatter camps and in farms, AIDS awareness is still very low," she said.
Reese stressed it "would be naive to think that is any cause for celebration.
"The rate of infection among South African youth, particularly young girls, is among the highest in the world. There are persistent behavioural trends, such as multiple sexual partners, that exacerbate the problem."
Reese said alcohol and drug abuse were contributing to the spread of HIV and AIDS.
"About 10 percent of young people reported that they had used different sorts of substances," said Reese, adding that alcohol abuse was the most common, with 10 percent of those surveyed saying they had used drugs and three percent "intravenous drugs."
"If this is a trend that is beginning to creep in... it's clearly something else that we need to be very mindful of and to be watching for," said Reese.
According to the survey, the highest prevalence rate was in eastern KwaZulu-Natal at 14 percent and the lowest, 4.8 percent, was in the northern Limpopo province, a relatively poor and rural area.
The UNAIDS agency estimates that one in nine people in South Africa, or 5.3 million people, were infected with HIV and AIDS at the end of 2002 -- one of the highest rates in the world.
South Africa's cabinet approved in November the outline of a plan to provide anti-retroviral drugs for those infected with HIV/AIDS after the government lost several court battles with lobby groups seeking free treatment for all sufferers.
The government has started to roll out AIDS treatment in three provinces in the country, but the lobby groups have said more needs to be done to treat the infected.