The principal of Rangiora High School says the cancellation of about 80 NCEA exams disrupted by a fire alarm on Tuesday has upset pupils and teachers.
A year nine student set off the fire alarm as a prank, causing those sitting exams to flee the school hall.
The student has since been suspended.
Principal Peggy Burrows says normally students stay seated briefly while staff find out whether or not the alarm is false, but many did not follow the procedure.
Mrs Burrows says because there was a chance for pupils to discuss the exam it cannot used and a derived grade based on previous school work will be given.