Campbell-Smith said her daughter phoned her "and I could tell how shocked and upset the girls were being compared to the terrorist organisation''.
When Campbell-Smith visited the school and spoke with staff, she was told the girls would no longer be allowed to take part in the Top House school fun day planned for that afternoon.
"I was shocked for the girls. Not only were they likened to ISIS but it's the second-to-last day of school and they took the event away from them."
Campbell-Smith said Year 13s did pranks at the end of the year and the girls' efforts were tame compared to other schools.
"They obviously respect the Christian side of the school and toned things down ... They didn't go into the junior school where the younger children may have been frightened."
Campbell-Smith said, in her view, the response from the teacher and the school was ridiculous. She was pleased the girls were eventually allowed to take part in Top House after other parents also complained.
Another parent, whose daughter would not be identified, said the school's response and ISIS comment were "over the top".
"It was the way (the teacher) put it. It was quite... an almost hysterical voice."
The teacher said they did not think it was appropriate "in these times, with what people are dealing with", the mother said.
Principal Eoin Crosbie said sometimes the school had to deal with end-of-year pranks but "our goal is to minimise these so as to not have them impact on the good things that happen as our Year 13s leave".
Mr Crosbie confirmed there was a water fight at the school on Thursday and students involved were disciplined by being withdrawn from part of the school's activities. Matters around how this was dealt with would be followed through using normal complaints processes and procedures, he said.
Mr Crosbie did not comment on the ISIS remark.
End-of-year pranks at New Zealand schools have been in the news this week.
Hamilton Boys' High School student Kyle Kirsten suffered a deep gash to his leg after a group of six topless girls from Waikato Diocesan School pranked the boys on their school field.
In Rotorua, about 30 Boys' High students ran through John Paul College wearing nothing but their underwear.