John Kent has a couple of good books, worth a read if you can get them. They are available from some libraries, save you buying them.
http://www.penguin.co.nz/products/97...-fishing-guide
http://www.penguin.co.nz/products/97...-fishing-guide
Fish and Game website also has information on regulations, rivers/lakes, access etc.
http://fishing.fishandgame.org.nz/fr...ng-new-zealand