The most comprehensive survey of sexual violence in the State will be published in April by the Dublin Rape Crisis Centre (DRCC).
The survey has been described as a "landmark piece of research" by Ms Geraldine Connolly, head of the centre's clinical services.
Some 3,100 people were randomly chosen and interviewed at length in the survey, which was conducted by the health research unit at the Royal College of Surgeons.
"It establishes the incidence of sexual violence on a national level for the very first time. It's astonishing but this has never been done before," Ms Connolly said.
An embargo has been placed on the findings, but it is understood that preliminary results are dramatic. It is understood the survey shows significant under-reporting of sexual crime and highlights the reluctance of people to seek help following an assault.
It also outlines people's attitudes to sexual violence and their perceptions of the barriers to accessing services.
In 2000, the DRCC found only 28 per cent of victims of sexual crime had reported the offence to the Garda. Ms Connolly said the findings would be of particular value in developing policies on sexual violence.
Preliminary statistics for last year indicate a substantial rise in the number of telephone calls to the rape crisis centre's helpline. The most significant increase appears to be in the area of recent rape, particularly in the last six months of 2001. The number of calls from other rape victims and from adult survivors of child sexual abuse has also increased.
Some 8,150 people called the Dublin Rape Crisis Centre in 2000. Ms Connolly said she expected "quite an increase" in this figure in 2001.
She encouraged all victims of sexual crime to seek help. "It will make such a difference to them and helps them to live full and productive lives again," she said.
Like many agencies. the DRCC has problems finding volunteers for its helpline. "People are very busy now. Not only that, but they have long distances to travel to and from work so it's very difficult for people to get time to volunteer," Ms Connolly said.
The DRCC helpline can be contacted at 1800 778 888.