Ms Crabbe, who lives in rural Victoria, will today offer a training day in Dunedin, on ''Sex ed by porn? Pornography and its impact on youth''.
Relationships and sexuality were ''really important'' and were a ''normal and healthy'' part of life, she said in an interview.
Many people did not realise how extensive and aggressive internet pornography was, and that an estimated third of overall internet use involved it.
One study had shown that more than 90% of boys, aged 13 to 16, had seen pornography, as had more than 60% of girls, and 88% of scenes from the most popular porn included ''physical aggression''.
Internet pornography was a ''poor and problematic'' sex educator.
''We can't afford to leave young people's sex education to the porn industry,'' she said.
Efforts should continue to limit viewing of pornography by young people, but other ''multiple strategies'' would also be needed.
They included helping older people realise how accessible pornography was in influencing young people's sexual expectations and behaviour.
She also sought to educate people who supported youth to ensure they could ''help adolescents work through, and critically analyse the messages porn presents.''
Today's one-day conference aimed to support those who work with young people in a social service, or through primary prevention, counselling, youth justice, family violence, police, academic research, and those with a mental health perspective.
