New Zealand features 3 cellular carriers: Vodafone, 2Degress and Spark. Their prices and features are very similar. Vodafone and Spark tend to have better coverage and quality of service, especially outside of the big cities. 2 degrees offer cheaper data, especially in bigger cities.
Technically, all overseas mobiles can be used in New Zealand, by just putting a local SIM card in your phone. Please advise the local provider, whether you need a normal, micro or nano SIM. SIM card are available in the providers shops, which can be found on Queen Street all over the place.
Please note that some cellphones have a SIM lock established by your provider that prohibits to use the phone in a different network. Please contact our reception and we will advise you of how to get rid of the SIM lock.