Many of the children in a principal's collection of 'objectionable material' were the same age as his pupils.

David Latimer pleaded guilty to 25 charges of possessing objectionable material this morning for a large collection of child pornography.

Stop Demand founder Denise Ritchie says the case was particularly alarming because the material involved very young victims and most appeared to be the age Latimer cared for at Rangeview Intermediate.

"Here we have a school principal who has a sexual interest in children. It's been a sustained interest and he proactively put captions on a number of images."

She says the possession of such images directly relates to the abuse of children, and that without demand, the abuse would be prevented.

"Of course without people like Latimer wanting this material and seeking it out, these children wouldn't going that kind of trauma."