O'Connor said the school would continue to ask for the donations, despite the Education Ministry ordering Auckland Grammar and Cornwall Park in strongly worded letters to stop asking parents to pay.
"Tim O'Connor is right in what he says," Drumm told the Herald on Sunday. "His argument is reasonable and sound. It costs a lot of time, effort, money and manpower to process out-of-zone applications and the $30 donation we ask for covers only part of these costs.
"Applications don't just have to be processed, they have to be followed up and scrutinised to make sure the information we are receiving is correct and the ballot is fair and proper.
"Often parents will apply to a number of schools that are out of zone so there is no guarantee they will take up a place at our school even if it is offered to them.
"We then have to start again with someone else if they turn us down, adding to costs.
"All of this uses up huge resources, mainly involving our support staff. The money that is used to do this could be getting put to better use elsewhere, so I don't think asking for a small donation that is not compulsory or is in any way enforced is unreasonable at all."
Katrina Casey, head of sector enablement and support for the Ministry of Education said schools were recently reminded in its School Bulletin that a fee could not be sought by boards to enter a student into a ballot for out-of-zone places.
"We reminded the schools that charging a fee could also create an inference that enrolment at the school would be secured if the payment is made," she said.
"If a school seeks a donation in connection with enrolment, the school needs to make it clear that the donation is optional and that there won't be any disadvantage to the consideration of the child's application if the donation isn't paid.
"We will be reminding schools of this if we became aware of further schools seeking fees from students to enter a ballot, or seeking donations that create any inference that they may be a condition of enrolment."
Cornwall Park District School principal Janine Irvine said the school stopped asking for money and refunded parents as soon as it was told the request breached the rules.