"Forest Fungi Field Guide" by Clive Shirley is the best book there is available on New Zealand fungi. It has something like 450 photos in it.

To obtain this book, go to: http://www.hiddenforest.co.nz/fungi/index.htm



There is a good New Zealand-written book worth getting if you want to know more about which mushrooms to eat (or not to eat!):
Edible and Poisonous Mushrooms of the World by Ian R. Hall, Steven L. Stephenson, Peter K. Buchanan, Wang Yun, Anthony L.J. Cole


A useful book to have is : Mushrooms and Other Fungi of New Zealand (Reed New Zealand Nature Series) by Geoff Ridley and Don Horne. Usually advertised on Trademe.