Where are you thinking of? I've spent some time down there on a few occasions, most recently earlier this year.
North Island? South Island, both?
Here are some shots and details of Tongariro area in the central North Island from that trip. Highly recommended!
http://www.14ers.com/php14ers/tripreport.php?trip=11405&parmuser=nyker&cpgm=tripuser 
