Horsham police have warned child pornography is prevalent in the Wimmera.

Police are investigating Wimmera based `sex texting'.

Sex texting is a phenomena that involves youths texting sexually explicit pictures of their naked body parts to each other to indicate they would like to form relations.

Detective Sergeant Stephen Walker said Horsham Crime Investigation Unit had two active investigations into sex texting and could launch a third investigation.

He said Horsham police had seized mobile phones containing naked images and video footage of sexual acts. He said it was alleged teens had uploaded footage onto YouTube.

He said the footage featured Horsham girls aged 13 and 14.

"Horsham CIU now has evidence that the making and possessing of child pornography is rife in the Wimmera area in the age groups between 13 and 21," Det Sgt Walker said.

"Young persons, with the latest technology mobile phones, being the major offenders."

Det Sgt Walker warned that young people risked being convicted, jailed and placed on the Sex Offender Register by sharing naked photos of themselves and sexual video footage with their peers via technology.

He said possessing child pornography carried a maximum penalty of five year's jail.

"What we know is only the tip of the iceberg," Det Sgt Walker said.

"All the photos and videos are of Wimmera children, Wimmera boys and girls. It's definitely here.

"We don't think kids realise they are breaking the law and committing serious sex offences."

Wimmera Centre Against Sexual Assault co-ordinator Jo-Anne Bates encouraged sex texting victims to approach CASA or Horsham police.

She encouraged parents to sit down with their children and talk about sex texting and sexual assault.

She said victims often felt inappropriate guilt. Ms Bates said children were children and even if they had consented to sex with an older person they were still a victim.

"This isn't Melbourne-based. Sexual assault happens right across the world, right across the state and right across the Wimmera," she said.

Ms Bates said it was important youths were aware that once they sent information technologically it was public property and no longer in their control.

She said paedophiles could upload explicit images in chat rooms.

Ms Bates said reporting child pornographic images to police or CASA could help victims.

"It stops that person becoming more vulnerable," she said.

"Hopefully that young child can then get support."

Ms Bates said if parents found sexual explicit material on their children's phones it was important they responded in a supportive manner, rather than punishing their children.