"Ms Gibbons reacted to the situation on the day while she was still angry and then found 'evidence' on Monday to support her harsh punishment," Mrs Vercoe said.
"These are good students who have given the school everything while they have been there and to have all their hard work over five years stripped because of one misdemeanour is not right."
Mrs Vercoe said the students' well-being had been damaged, with many feeling dejected and depressed.
"The punishment did not fit the crime which is why we as parents have fought so hard against it. Our girls are hurt and depressed by the ... actions of the school, including leaving all the students involved off the Year 13 celebration photos in the final assembly."
Mrs Vercoe said she had laid a formal complaint to the New Zealand Teachers Council and would consider taking the matter to the Ombudsman.
Former head girl Moerangi Vercoe, daughter of Karri-Ann Vercoe, said the students felt they had been treated like criminals.
"On the day the incident happened we had gone back to the school with the intention of apologising but instead we were sat down, screamed at and told to hand over our badges, without getting the chance to speak."
Moerangi said she felt deeply hurt by the school's action during and after the incident.
"I had to sit my exams at John Paul College because of the strain at my school, but what hurt me the most was not being able to speak to my girls and at least apologise for my actions.
"To this day we still haven't had the chance to tell our side of the story.
"When my head-girl badge was stripped, Ms Gibbons said I had disappointed her, but she disappointed me more because all year I defended her saying she was a fair and humble principal, and then she goes and treats us with so much disrespect, that really hurt me."
Moerangi said she was now fighting the punishment for the sake of the students still left at Rotorua Girls' High School.
"Ms Gibbons said leadership was a lonely journey but it doesn't have to be.
"This ordeal taught me that leadership isn't defined by your badge, but your desire to fight for what you believe in and those who stand with you."
Ministry of Education head of sector enablement and support Katrina Casey said they were notified of the incident by the school and parents of the students.
"Since the incident we have met with some of the parents of students affected and with the principal.
"An independent review, which has been welcomed by the principal, will be undertaken so that the matter can be resolved by all parties."
STATEMENT FROM THE SCHOOL
Prior to this incident occurring the school clearly explained to all Year 13 students what our expectations were around the last days of the school year and that there would be consequences for any actions that were not acceptable. Students in senior positions are fully aware of their responsibilities and that the school expects them at all times to 'Ka Hikitia' (school theme-To Step Up! ) into their leadership roles.
The school collected evidence from different sources, sought advice and carefully considered all of this before coming to a decision which included standing down students and removing leadership positions where applicable. The school formed the view that the manner in which the students left the school seriously compromised their safety and that of others, along with there being mass disobedience of a senior member of staff.
The Board is committed to ensuring that it follows best practice at all times and will participate in an external review in conjunction with the Ministry of Education.