Two more were suspended, while six other girls had been stood down. One of the girls expelled would complete her exams after studying at home, while the other two would be helped to find new schools.
Mr Gargiulo said the fight stemmed from bad blood between two groups of kids. "It had been going on and on and on, and unfortunately never came to our attention or youth workers would have been involved."
He said the students at the school were upset at the attention the fight had received, and particularly the damage it had done to Manurewa's reputation.
"I've told them in assembly the only way to fix that is to be good role models. This doesn't affect our achievement or other good working going on in the school. We have to have a positive mindset, park in and move on," he said.
Mr Gargiulo wrote a letter to the Herald about the stereotypes which affect the schools, and how the fight didn't represent all its students.
Footage of the fight was uploaded to Facebook and viewed more than 800,000 times, the latest in a string of violence incidents involving high school students to appear online.
Last month a mob of schoolboys from three different schools turned on a 19-year-old who was picking his little sister up from school, when he tried to stop them attacking a younger student.
Two students aged 17 and 18 were charged with assault for their part in a 60-student fracas between students from De La Salle and St Paul's colleges at Orakei Train Station last month.
In May, a 15-year-old girl was arrested following an assault in Kaikohe that was filmed and posted In March, footage showed a girl crying as she was hit by another girl, before the fight was eventually broken up by bystanders.
Police have urged parents to keep an eye on their children, and know who their friends were.
