Mr Burden said parents had high expectations on everything from student achievement to ensuring a safe environment, and the other side of that was accepting any rules deemed necessary.
Auckland Grammar School inspects boys' hair at the start of the year to make sure it is short enough and clean.
Headmaster Tim O'Connor said boys were subject to a monthly grooming check, including hairstyles.
"It's all part of the package in terms of trying to set tone, culture and overall standards in a conservative boys' school."
Sheryll Ofner, principal of Selwyn College in Kohimarama, said it had no requirements on hair length or style, only that colours were not unnatural.
"It's really important schools are backed in terms of requirements around uniform, because lots of people try to push the boundaries."