Year One boy engaged in "sexual behaviour" at a Melbourne school.

A Melbourne woman, who identified herself as “Kate”, has told ABC radio that a Year One boy at a local school engaged in sexual behaviour with female students, including the removal of clothing and the simulation of oral sex.

“There were several incidents including him dragging girls into toilets, forcibly removing their clothes, and other incidents including kissing younger girls’ private parts,” she told told Jon Faine on 774.

The behaviour also included “making girls get on their knees and open their mouths to put his privates in their mouths.”

Kate says her sons witnessed the incidents and were left traumatised by what they saw.

She indicated that the parents of the victims were silenced and that the broader community was not informed about the incidents.

“I don’t think we needed to be told all the gory details, but we needed to be told that there had been sexual behaviours happening in the schoolyard and that we needed to talk to our children to see if they had seen anything or been involved in anything.

“It turned out there were quite a lot more children involved than the school was originally aware of.”

Kate says the incidents occurred in October last year and when she was made aware she made a complaint about the incidents to the police. She he was referred to the Department of Education the Department and Human Services who told her there would be no investigation.

Education Minister James Merlino said he could not comment on specific cases but admitted age inappropriate sexualised behaviour was “distressing”.

“These can be a result of behaviours they’ve observed and can’t make sense of, they may be victims themselves,” he said.

The school was not named in the report.