Apparently GLA CO2 stuff is great
I have bought non-CO2 stuff from them before and their customer service is excellent
Remember though that they are an American company, so the CO2 regulator and bottle will have a different thread ( so I doubt that the bottle will be refillable in NZ), and the solenoid on the regulator will run on a different frequency and voltage. Ask them though if they can make one to NZ's specifications. I have read on the testimonials that they can custon-make stuff.