Yeah heaps of places & setups on the North Island. I had a few nice session at Mount Maunganui over Christmas, & the Taranaki is epic for its wind & waves. Never sailed around Auckland, but I hear it has its days.
If you want pretty much guaranteed wind you can certainly come down to Wellington. One of the windiest cities in the world & you can get out on average 4 out of 7 days here. Both wave & flat water spots anything from a 10 minute to an hours drive from the city center plus a friendly bunch of kiters. Just pack a small kite