"This is such a disappointment, the excitement is killed for those who actually worked really hard to gain those leadership positions.
"In life, not everyone can be leaders, it's not the way it works. There are losers, not everyone can win."
She said trust in the principal and the teachers who had agreed to the new structure had gone.
"There is no honour in being a prefect at this school because it is simply gifted to you.
"It's not a realistic way to prepare these students for life. You look at any employment environment and there is no way you're going to find one where everyone is a leader," she said.
However, principal Steve Lewis said the structure change was about extending leadership responsibility.
"We wanted to be able to give all our students the chance to learn, experience and expand their leadership potential.
"Previously the prefects were classed as one category and students could apply for other categories such as house captain and the like. Now those other leadership roles still exist, but they all come under the one category of prefect."
Mr Lewis said the school had not received any calls from concerned parents.
"It is something we are trialling and if it doesn't work, we are not opposed to going back to the old system. However, we are not going to stick to an old regime just because it's traditional. We are not a school that looks at leadership in an elitist way.
"We have to take into consideration the year group and this group of senior students show strong leadership qualities," he said.