Private Auckland school King's College will consider new measures to report bullying after some junior students were terrorised by a group of older students.
Kings College is investigating an incident where six Year 12 students put pillow cases on the heads of three Year 9 students and made them march outside in the middle of the night last week.
One of the Year 9s has also claimed one of seniors hit them across the back.
The school's new headmaster, Mike Leach, said all six senior students had been suspended following what was a prank which went too far.
"Students won't learn unless they feel safe, and one of the things that is really not negotiable is making kids not feel safe, terrorising them, bullying them, ridiculing them," Mr Leach said.
A decision about whether to allow the Year 12s to return to school would be made at a school board disciplinary committee this week, he said.
The police in Manukau said they had not received any complaints.