The opposition says the condition is a dangerous imposition on a committee already equipped to protect witnesses and undermines the democratic process.
Catholic schools have released internal incident data, as parent groups and the union call for greater transparency on violence.
Joining students marching through Canberra, former chief scientist Penny Sackett said the movement might be more effective than 25 years of UN climate summits.
It comes after recent revelations about attacks in The Canberra Times and research finding Canberra principals face the highest rate of violence in Australia.
The minister defended her record on school violence amid revelations that complaints had been made about violence at a Canberra school for more than a year.