Letting children play violent video games teaches young people that "life is cheap", a Rotorua primary school principal warns.
The comments follow two stabbings involving school students in Auckland this week - news that shocked the country.
According to figures released by the Ministry of Education, Rotorua schools dished out at least 56 formal disciplinary actions last year for physical assaults on classmates, plus eight or more for assaults on school staff.
A handful of students were disciplined for bringing weapons to school.
Otonga Primary School principal Linda Woon said while violence didn't appear to be increasing at her school, "two in one day made you think about it".
Failure to monitor violent video games and television shows was teaching kids that "life is cheap", she said.
"What monitoring is being done about that and the values that are involved in those games?"
In the event of an incident like a stabbing, Ministry of Education trauma teams responded quickly, bringing with them resources including counsellors.
"They're a huge help in any traumatic event like that."
Their online resources also helped schools prepare for what could happen, she said.
An 11-year-old boy is in a critical condition this week after he was stabbed with scissors during a fight with another pupil at Pacific Christian School in South Auckland on Tuesday.
It's believed the boy was stabbed in the head.
Meanwhile, a teenager from another school was stabbed in the neck and another injured in an after-school fight in a Mangere car park hours later - just 4km from Pacific Christian School.
Police said the two incidents were unrelated.
New Zealand Educational Institute national president Judith Nowotarski said this week's stabbings were "extraordinary", but sadly not one-off incidents.
"It's a tragedy for the children, for their families and the schools. Events such as these leave a lasting impact and really bring to light other [problems] outside of school," she said.
[Violence] is usually a symptom of something else."
Ms Nowotarski expected to see a nationwide reaction to the incidents.
"Schools want to create environments where children feel safe so when something like this occurs, it does bring to light, 'Are we doing all we can?"'
A 2013 survey of more than 700 primary and intermediate teachers by the New Zealand Council for Educational Research showed 14 per cent had occasionally felt unsafe at school, and 11 per cent in their classroom.