Police have arrested nine people wearing gang colours after an attack on a Hutt Valley High School student on a college sports field.
Police said a series of fights broke out shortly before 3pm after a group of three adults and six youths, aged 14-17, arrived at the school and confronted a student about a previous fight.
Inspector Geoff Gwyn said a series of scuffles broke out as about 30 students went to aid their schoolmate.
About a dozen police were needed to quell the fighting and arrested the nine members of the group, who the school's principal told TV3 were wearing gang colours.
They have been charged with unlawful assembly and will appear in court tomorrow.
Mr Gwyn said one female student received a cut to her head when a rock was thrown into the melee.
"The group had been told to leave the college grounds earlier this morning but returned this afternoon and sought out the student," he said.
"This sort of violent behaviour is unacceptable and won't be tolerated by police or the college."
None of those arrested were involved with the school.
A police spokeswoman told NZPA the three adults were unemployed, while the youths were not in school uniform.
The TV3 report did not say which gang the group were associated with.
