"Each of the students will be expected to meet a range of conditions before they are considered for re-enrolment next year," King's College said.
The school said a disciplinary committee of its board of governors met yesterday with the students involved in the incident, which occurred last Thursday. Those students' parents and members of their support networks were also at the meeting.
"The Board regards any bullying as a serious issue and was very disappointed with the actions of the students involved," King's College said in a statement this morning.
"The students are remorseful and realise their behaviour has caused distress for the Year 9 students involved, the wider student body, College families and staff."
The school said students accused of bullying were also concerned about the impact the incident had on the student body and the younger students' well-being.
The junior students were offered counselling.
Headmaster Michael Leach said he would reinforce current anti-bullying processes and introduce new programmes in which all students would have to take part.
"Some of these will be based on resource materials provided by the Ministry of Education, and the school is grateful for this assistance," King's College said.
This week, a parent from the school told the New Zealand Herald the younger boys allegedly had their faces covered with pillowcases and were screaming in fear.
The father said parents had been horrified to learn of the incident