One in five high school girls have experienced unwanted sexual behaviour in the past year, a new report has found.
The Family Violence Clearinghouse report (PDF, 359KB) found that violence in youth relationships was a big issue, and received far less attention than violence in adult relationships.
Youth & Cultural Development general manager Annie Watkin works with young people who have suffered abuse at the hands of a partner or parent.
She said the findings accurately reflected what she saw in her office every day.
"Many young people normalise violence in their own home, and then they accept that in their relationships."
Ms Watkin said there was always help available for young people stuck in abusive relationships, and all they needed to do was reach out.
The report involved research from agencies such as the Education Review Office and Women's Refuge, and found that the majority of unwanted sexual behaviour came from boyfriends, girlfriends or friends.
The author of the report, University of Otago sociologist Dr Melanie Beres, said schools have a big role to play in educating young people about healthy relationships and consent.
Dr Beres said some schools were not doing a good enough job of talking about the issue.
"Some schools have great sex education, while other schools aren't doing much... and missing out on that really critical relationship component," she said.
Most teachers did not have the skills needed for teaching about healthy relationships and consent, she said.
"Teaching sex education is a lot different to teaching maths or history... teachers need specialist training to deliver these programmes."
Christchurch Boys' High School headmaster Nic Hill said the teacher, not the teaching, was what mattered.
He said Boys' High had compulsory sex education classes for Year 9 and 10 students, and worked with the police to teach students about consent.
Mr Hill said it all came down to having good role models.
"It might be an individual boy going to a teacher who he knows he can talk to," he said.
Mr Hill said the schools looked to employ teachers who were good role models and demonstrated positive values to their students.