Wellington is supposed to be the best place in NZ, but I'd suggest you check other forums (like PP) for more info.
2 or 3 years ago I'd have recommended the Splash Club, it's above one of the strip joints (Mermaids??) on Courtenay Place, with a bar where you mingle and chat with the ladies before choosing one to take to a room. Had some fantastic sessions there, but my last visit ~15 months ago was a stinker ...... pretty sure they'd changed management. Gone were the days of being able to relax in the lounge and the girls being genuinely friendly, now management try and get you to prepay for a session before even entering the lounge and seeing the girls!! Fuck that, I threatened to walk and they relented, but once inside the girls were the most mercenary I've ever encountered. Some hotties amongst them for sure, but every single one was pushing for a double session (twice the money, half the work for them) and incredibly vague about their service. They'd also removed the 30min and 45min session options, so I could smell I was going to pay up for an hour that would turn into a "blow and go" session, which is exactly what I got. On previous visits I'd often do 2 or 3 girls in a night, that last time I re-entered the lounge after the "blow and go" and the next girl that approached me asked me to book her for 2 hours and pay her a ridiculous tip, all before we'd even exchanged names. Fuck that, out of there and haven't returned.
I've also been to Femme Fatale in Auckland. Very vague on the scene there, but it was a similar set-up, lounge where you mingle and pick a girl to take upstairs. Reasonable place. All said and done NZ is great value for cauc ladies, you're generally paying about $180 NZ Peso's per hour, which is like AUD $140.