The tougher line follows an Ombudsman report into horrific assaults where nine junior boys at Hutt Valley High School were chased down, partially stripped, then sexually violated with a screwdriver, scissors and drills by senior students in 2007.
The report, released last year, recommended compulsory anti-bullying programmes in secondary schools.
Moana Hawkins - a mother of a 14-year-old Flaxmere College student left with a fractured spine after an attack at school - said schools should go further and report all serious violence to the police.
Hawkins' daughter, Adriana Kemp, was released from hospital this week after more spinal surgery.
Mandatory police notification is also backed by Helensville mother Mellissa Anderson - who received diversion after she assaulted teens who allegedly punched and bullied her 13-year-old daughter Summer Anderson.
Schools were quick to jump to their own defence, she said, and police and schools should work together to report serious violence.
"There is so much violence happening in schools at the moment that most are unaware of. Had my case not hit the headlines it too would have gone under the radar."
The assaults on Adriana and Summer had gone unreported by the schools, as had the attack on the nine junior boys at Hutt Valley High School. The Ombudsman's report found guidelines on stand-downs, suspension, exclusion and expulsion were lacking and were normalising a culture of violence.
The Ministry of Education believed leaving the responsibility with schools was appropriate and that each incident should be treated on a case-by-case basis.