There has been a sharp increase in disciplinary action against children who assault their peers.
Stand-downs, suspensions and exclusions for assaults on other students rose nationally in 2023, and doubled in some regions.
Schools in 2023 made 11,575 stand-downs for assaults on other students, 23 percent more than in 2022 and 28 percent more than in 2019 - the year before pandemic lockdowns prompted a drop in disciplinary figures.
In Nelson/Marlborough/West Coast and Bay of Plenty/Waiariki the number jumped more than 40 percent between 2022 and 2023, with the South Island regions' figure 92 percent higher than in 2019.
Stand-down numbers for all causes, including assaults, dropped in the first years of the pandemic, but are now considerably higher than pre-pandemic.
In 2019 schools made 22,280 stand-downs, dropping to 18,189 in 2020 before climbing to 25,142 in 2022, and to 30,711 in 2023.
The increases far outstripped 2023's 2 percent increase in school enrolments.
Physical assaults have consistently been the main reason for stand-downs, followed in recent years by vaping/smoking and continual disobedience.
Physical assaults on other students were also the main reason for suspensions and exclusions in 2023.
The 1192 suspensions for physical assault on other students in 2023 were 40 percent more than in 2022 and 50 percent more than in 2019.
Waikato schools suspended twice as many students for assaults in 2023 as they did in 2019.
Schools made 449 exclusions due to physical assault on other students in 2023, 54 percent more than in 2022 and 59 percent more than in 2019.
Earlier this year, the Education Review Office said national action was needed to rein in critical levels of violent and disruptive behaviour.
The new figures showed schools in some regions were making fewer stand-downs and suspensions for offences involving alcohol and drugs than before the pandemic.
Principals told RNZ the increase in bad behaviour was an after-effect of the height of the pandemic.
Greymouth High School principal Samantha Mortimer said she had noticed an increase in assaults, but it was not a constant problem.
"Often it's when you get lots of young people together who they might have come from different primary schools, there might be someone who moves into the area, there might be some kids with incredibly complex needs."
Mortimer said it was important to use stand-downs carefully and work hard to ensure students who misbehaved were helped to improve their behaviour.
Often, students who were disciplined in Year 9 or Year 10 were never a problem again in later years, she said.
In Bay of Plenty, where physical assault stand-downs were up 41 percent over 2022, Te Puke High School principal Alan Liddle said much of the problem was due to the pandemic.
"What we're all trying to come to grips with is the effects that have come out of the pandemic in terms of people's resilience and people's tolerance and I think you can see that in society in general.
"There's a lot of anxiety among students. You can imagine that they've been told for quite a bit of their life to actually stay indoors and stay away from people and then they're now told to come to school and that's not a quick fix."
Liddle said schools had not received a lot of support for those issues.
"There needs to be a big change in terms of what support's put into schools for that," he said.
"You'll get peaks. It's not like it's a constant thing that's been rising. There are incidents that happen ... but certainly overall there's an increase."
Secondary Principals Association president Vaughan Couillault said students in Years 10 and 11 were more likely to have dysfunctional behaviour.
He said pandemic-related disruption to schools in the past four years hampered some children's ability to get along with one another.
"We've been experiencing this over the last 18 months where students seem less equipped to deal with things in a pro-social way when they get into conflict or disagreement, they're more inclined to use a physical response than a social one."
Couillault said students were not only more likely to fight, but the violence was often more serious.
"We're certainly experiencing ... a greater willingness to engage in physical violence and to perpetuate when, in a clumsy term, the job is done," he said.
"We're seeing increasing levels of carrying it on, taking it too far."
