A 14-year-old Whangarei student is in hospital with a skull fracture after being attacked by a classmate.
Whangarei Boys' High School says the student was punched in class in a ferocious and unprovoked attack on Wednesday afternoon that left him with concussion and a broken brow bone and nose.
The school has suspended the attacker and called in police.
Headmaster Al Kirk says the attacker had teacher-aid support last year because he was considered a risk, but did not offend during that time.
Mr Kirk says the boy had not been at school often enough this year to be re-assessed for support, and Wednesday's attack came out of the blue while students were taking tests in the school hall.
He says he has never seen such an assault in his 24-year career.
Police say the boy will be dealt with in the Youth Court.