Her research, for the Auckland Sexual Abuse Help Foundation and Tu Wahine Trust, found many teenagers internalised their parents' messages and "struggled to envisage an example where the victim would not have been responsible for what happened".
"If they are in part responsible, then young people didn't feel it was sexual violence - and then we wonder why they are not disclosing," she said. "At a time in their lives when they are seeking independence and taking risks, they are being warned to be careful. Parents are warning them not to be out late or not to wear those clothes, and they did, and it happened."
Help Foundation youth counsellor Carol-Anne Weaver said sexual violence by strangers was rare. Most young people she worked with were abused by people they knew in situations where they normally felt safe.
"It could be anything from being in a park with a group of friends to being at the beach, being at a party, perhaps other family members bringing someone into the house in their own home, watching a video. It's very varied," she said.
Ms Woodley said young people were afraid that if they told anyone it would damage their own reputations and bring shame on their families, especially in Pacific and Asian cultures.
Rape Prevention Education founder Dr Kim McGregor said self-blame was the number one reason victims did not tell anyone.
She advised parents to give their teenagers strategies to deal with sexual pressure rather than just urging them to avoid it.
"They could say what pressure is," she said. "If they have only heard that sexual violence is stranger rape, then they don't recognise when they are being pressured and manipulated and someone is getting them drunk in order to go and take advantage.
"If we could describe those situations, like if you are drunk then you can't make decisions about sex - if we arm them with a lot of information like that, that may be helpful."
She said rape educators found that most high school students did not even know it was illegal to have sex with someone under 16.
Auckland University psychologist Nicola Gavey suggested encouraging teenagers to "keep an eye out for each other" and to watch out for signs of boys pressuring girls for sex.
Teens say
• "I think most young people would feel foolish, they would blame themselves. But they would see it as a part of life."
- Pakeha teenager
• "My mum would blame me, definitely. My dad would be real disappointed in me. I would never be allowed out again - and I mean never."
"I think some of our parents and elders would ... not blame us exactly, but they would think if we had stuck to our old ways and done the right thing, like not gone out in the first place, it wouldn't have happened."
- Pacific teenagers
• "My parents came to New Zealand for a better life for me and my sister ... If this happened, they would think we were to blame because it wouldn't happen back home. And they would blame themselves, too, for not being stricter."
- Asian teenager
Tips for parents
• Give teenagers strategies to deal with sexual pressure rather than just urging them to avoid it.
• Describe the kinds of pressures they might encounter and give advice on how to respond.
Encourage teens to keep an eye out for each other and watch for signs of people pressuring them.
• Tell your children it's okay to talk to you if something has happened.
