Thank you for your advise escapedtonez...sorry to reply so late..Hmm.
Clothing and footwear appropriate for the season that you will arrive in NZ (July is mid winter - note I'm in Hamilton this very moment as that's where I work and it is currently -2 degrees and we've had our first frost!!!) and dependent on the area you are going to.
Any prescription meds to tide you over until you can register with a GP in NZ. Don't attempt to bring any more than 3 months supply through customs.
Cash to cover expenses for the trip and the first few days after arrival as you may not yet have a bank account or an ATM card. If you bring through more than $10 000 you must declare it to customs and provide evidence that it is your cash and has been earned legitimately.
Passport and any travel tickets needed.
Confirmations for any accommodation or rental house, car etc.
That's about it for essentials, unless you are coming along with children.