Ms Gibbons said the dangerous behaviour left the school "very worried for the safety of the students".
"When our current Year 13 students were in Year 9 a previous student left the school grounds and lost her life while another was left with serious head injuries. The girls were deeply affected by the incident and as a school we never want that happening again."
Ms Gibbons said the Year 13 students were fully aware of the high expectations and standards required of them and the school was disappointed with their actions. "Our course of action was deemed necessary as the students willfully chose to leave the school grounds in a convoy of cars despite being asked to return to class."
Senior leaders at the school were among the students stood down for three days.
Head girl Moerangi Vercoe's grandfather Mike Jones said he was "really cross" with the school's reaction.
"These are very good children who had spent the day doing fun things and had decided to leave the school in the last two periods as a prank.
"They were summoned back to school and yelled at before being stripped of their badges and stood down."
Mr Jones said he was dumbfounded at the school's response to the situation.
"This reaction is affecting so many of the girls' lives and I just can't understand how the school could over-react to something that wasn't hurting anybody and was just some harmless fun."
Mr Jones said many of the stood-down students' parents had arranged a meeting with Rotorua Girls' High School principal Ally Gibbons today to discuss the disciplinary action.
"The punishment was so over the top, especially considering it was the last day of school and the girls were all really good students who had never done anything bad.
"We feel this is an excessive put down at a time when the students need to be focusing on end-of-year exams."
The students will be allowed to return to school on Thursday.