Two teenage girls have been effectively expelled from Auckland's Mt Albert Grammar School over two violent incidents, including one in which a man was beaten up in front of his daughter.

The school's board of trustees chairman, Greg Moyle, confirmed today that the 13 and 14-year-old students had been barred from attending the school. However, because of their age, the school legally has to find places for them at another school.

The younger of the two had been at the school for only five weeks.

Mr Moyle said the girls were in school uniform when they attacked a man at the St Lukes Shopping Mall, kicking him in the head as his daughter looked on.

In the second attack a fortnight ago the girls brawled with each other at the mall, tearing each other's clothes and pulling out handfuls of hair.

Mr Moyle said it was a sad event but not common at the school which has 2500 students.

He was trying to find another school for them or an alternative education.

"At the end of the day, despite the terrible thing these girls have done, they still deserve a decent education but it won't be at Mt Albert Grammar."

Mr Moyle said the security camera footage of the first incident was "fairly shocking".

A complaint to police was not an issue for the school or the board.

"What we have to do is to ensure the safety of our students at the school and these girls clearly would be an unsafe influence if they were allowed back into the school."

He said the girls had let down themselves, their parents, their families, the community and the school.

"I hope they take it on board and correct their ways...and they don't let this incident mar their future."