Tauranga Boys' College principal Robert Mangan told the Bay of Plenty Times suspensions were a last resort.
"Suspension, I believe, is a useful tool, a powerful tool, that we use after significant deliberation."
It was used only when it was for the greater good of all the staff and students.
Mr Mangan said there had been a downward trend in the number of suspensions at the school in recent years thanks to programmes aimed to reinforce positive behaviour. A suspension allowed the school to convey the seriousness of the problem to the student's family to get them on board and bring in other agencies, he said.
"Of the 37 suspensions it has resulted in eight exclusions. I see in that, that the vast majority of boys that are suspended are returned to school.
"I really think the important measurement is not the suspensions but the exclusions."
Otumoetai Intermediate principal Henk Popping agreed suspension was needed to encourage parents to get involved. "Suspensions are used to engage with parents and find a solution. In most cases we return them to school," he said.
"The predominant reason in our school is non-compliance with teachers - being rude and interrupting. It's really been a last resort to bring students and their parents together."
Mount Maunganui College principal Russell Gordon said he agonised over every decision to suspend a student.
"Honestly, the thing about this education business is that each one of those numbers represents a child whose education has been curtailed.
"I know that kid has been consigned to a life where the are likely never going to reach their potential."
Mr Gordon said suspension was only considered when a student was continually disrupting the learning of others.
"We have to weigh up the rights of that child compared to the rights of the students in their classes," he said.
The numbers have sparked calls for a major overhaul of the way schools keep difficult children engaged, with YouthLaw pushing for the establishment of an independent review function for suspension decisions.
Principals' Federation president Phil Harding said the number of suspensions was troubling. The education system needed to change the ways it kept problem students engaged - but he did not see any need for an independent review of suspension decisions.