Mt Roskill Grammar's five suspended students will front the school's board of trustees next week, principal Greg Watson says.

Teachers and pupils were forced to see off up to 20 "outsiders" who went to Bishop Viard College armed with a baseball bat and threatened students.

The Lynfield College student who led a group of armed teenagers to a classroom where they beat up a 14-year-old boy has been suspended from school.

The only penalty awaiting the teens in the Lynfield College attack: family group conferences.