What can I do if I believe I have been mistreated by the New Zealand Police?

If you are unhappy about the service you received from the Police, you can submit an Expression of Dissatisfaction online here.  If you have a serious concern you can make a formal complaint here. A 'serious concern' includes concerns:

• regarding misconduct or neglect of duty by a Police employee;
• regarding a policy, procedure or practice of the New Zealand Police; or
• regarding the standard of service you have received.

Further, you can complain to the Independent Police Conduct Authority here.
 
Other complaint options include writing to your local Police District Commander or making a complaint in person, which can either be at a Police Station or, by arrangement, somewhere else. You are able to bring a friend, relative, or lawyer.
 
YouthLaw and community law centres can provide assistance in exploring these options, and may be able to assist in writing and submitting your complaint.