One in three of the 4,000 women questioned by CIET Africa, non-governmental organisation, said they had been raped in the past year.
CIET researchers trying to find ways of arresting the alarming growth in sexual violence in South Africa said they were shocked by the finding.
Gang rape 'fun'
In a related survey conducted among 1,500 schoolchildren in the Soweto township, a quarter of all the boys interviewed said that 'jackrolling' - a South African term for recreational gang rape - was fun.
More than half the interviewees insisted that when a girl says no to sex she really means yes.
Many of those interviewed also expressed little knowledge about the need to use condoms and to practise safe sex.
'Intolerable'
The boys' opinions differed markedly from those expressed by schoolgirls, many of whom suggested that they were living in an intolerable sexual environment.
Levels of sexual violence differ across the country.
But BBC Correspondent Greg Barrow, in Johannesburg, says the city - South Africa's largest and its industrial hub - is rapidly emerging as the rape capital of the world.
He says the CIET survey will only serve to reinforce that unwelcome title.
CIET says it will be recommending a new approach to the problem in schools, and among the police and community leaders.
It also hopes to focus on the majority of men who do not rape and establish ways of raising their profile as community role models.
As recently as last week, South Africa's first black test cricketer, Makhaya Ntini, appeared in court on rape charges - to the dismay of those who saw him as a potential role model for young sportspeople.
Car hijackings up
The survey was released at the same time as the government's latest crime statistics, which reveal that the rates of murder and rape in South Africa had declined slightly during 1998.
The murder rate nevertheless remains at 52 per 100,000 - eight times as high as in the United States.
Car hijackings last year were up by nearly 9% on the previous year's figure, and the statistics also show an increase in the rate of burglary and mugging.
Country profiles
Fast bowler Ntini charged with rape
(14 Jan 99 | Cricket)
South Africa toy guns warning
(04 Jan 99 | Africa)
Ambush frees South African prisoners
(04 Jan 99 | Africa)
Firing on all cylinders
(10 Dec 98 | Africa)
South African police services
Operation Camelot
National Crime Prevention Strategy
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