Compliance Document for New Zealand Building Code, cl G1 Personal Hygiene
You should talk to your teacher or principal, or write to the school board.
If a school does offer gender neutral bathrooms, each facility must:
be in a self-contained unit,
have full height doors and walls to maintain full privacy, and
contain a toilet, basin and sanitary item disposal area.
Schools don’t have to provide separate toilet facilities for male and female students. If you’re asking your school to review their toilet facilities, it may help your case to remind them of this.