The Presbyterian Church offers a confidential complaints process. The Northern Presbytery has appointed people to independently advise and support anyone who wish to make a complaint about a minister, office bearer or church member. Please check your church notice board where a Complaints Process Notice should be displayed (it should display the date March 2016 in the bottom corner if it is current). This notice will have the details of the people you can contact. If you cannot find a Complaints Notice then please contact the Northern Presbytery office who will help you to be in touch with the appropriate person.
More details came be found here: http://www.presbyterian.org.nz/for-parishes/complaints-process