Rape Crisis Network Ireland has said a binge drinking culture is allowing sexual crimes to go unreported.
The RCNI has published new research looking at the experience of young people and the way in which they respond to issues such as sexual consent and sexual violence.
It said there are serious failings in the protection of children, which require a structured and urgent response from Government.
The RCNI said one consequence of the drinking culture among teenagers is that reporting sexual crimes or concerns is rarely considered.
It said this means young sex offenders are free to re-offend, causing trauma and lifelong harm to others.
It said older children need to be encouraged to develop skills around the issue of consent when it comes to sexual activity.
The study, Young People, alcohol and sex: What's consent got to do with it?, was carried out by NUI Galway researchers.
Respondents were agreed on the central role alcohol plays in Irish social life.
It was considered unusual for somebody not to be drinking on a night out.
The research found "levels of drunkenness" affected the way in which young people considered whether sexual crimes had occurred.
Participants were found to be cautious when it came to labelling sexual events as rape.
The report said that while there was consensus on the unacceptable nature of non-consenting sexual encounters, there can be subtle attribution of responsibility to victims as a result of alcohol consumption.
RCNI Executive Director Fiona Neary has described the research as "shocking".
She said it showed young people had an inability to talk about sex and had little grasp of the need to negotiate sexual consent.