A teachers' union says there's an urgent need for more funding to tackle violence in schools.
A new survey has found more than half of Northland principals feel ill-equipped to deal with disturbed students.
NZEI president Louise Green says many schools are crying out for help.
"That resource, that professional support is not always there, it doesn't come quickly...and it takes time for us to get the resources," she says.
Louise Green says extra teacher aides and hiring professional mental-health staff would be a big help.