Hi Mauied, where in the North Island are you going?
Further south there's the touristy Rotorua where they'll set you up for tours of bubbling hot mud pools, hot springs and Maori culture shows.
Not many tourists venture out of the Auckland area unless it's to go to Queenstown (in the South Island), but if you're heading down to the lower North Island I've got a few more things of note you may be interested in. Let me know.
I'm in Wellington (aka Wellywood) if you make it this far down.
Just in case you haven't checked it out hae a look here...
http://www.newzealand.com/travel/International/
Enjoy your stay.
Cheers