The Standard this week reported the aftermath of two young south-west men's crimes, including one who sexually assaulted five victims before he was 18.

He successfully appealed a 15-month sentence in youth detention, instead being removed from the sex offender's registry and placed on a community-based order for 12 months.

In an unrelated case a then 20-year-old man sexually assaulted a 15-year-old girl while on a football trip. He was jailed for at least six months.

The offending had a catastrophic impact on the victims' well-being.

Jodie Hill, chief executive at Women's Health and Wellbeing Barwon South West, said gender inequality was at the heart of violence against women.

"To prevent violence against women before it happens we need to be teaching men and boys about positive forms of masculinity and creating a culture where women and girls are respected equally," she said.

"The young age of some of these perpetrators shows us that it's never too early to start teaching our boys about how to be good men."

A recent Australian Institute of Health and Welfare report revealed that for those aged between 16 and 24, offending by adolescents (18 per cent) was more common than by adults (12 per cent).

The most common classes of perpetrators were other known young people in non-romantic relationships, followed by parents or caregivers in the home and then other known adults.

Ms Hill said the spike in younger perpetrators was alarming and highlighted how much work was still left to do in terms of prevention of violence against women.

"There is clear evidence about what the drivers of violence against women are and they are certainly firmly linked to male attitudes around control, power, and dominance," she said.

She said the condoning of violence was a big contributor.

"Many people don't openly condone violence but what it can look like is language that minimises the impact, shifts the blame to the victim and trivialises incidents," she said.

"It's just not OK to send signals that condone violence."

Ms Hill said she would love to see more men taking a proactive position in role modelling positive, respectful and equitable behaviour.

"And more than that, men have a powerful influence over other men and boys," she said.

"So it would be great to see more men very explicitly calling out bad behaviour and clearly setting expectations about positive male behaviours that ask young men to stop the violence and to treat women with respect."