Electricity is supplied throughout New Zealand at 230 / 240 volts, 50 hertz. Most hotels and motels provide 110 volt ac sockets (rated at 20 watts) for electric razors only. For all other equipment, you’ll need an adapter / converter, unless the item has a multi-voltage option.
Power outlets only accept flat three or two-pin plugs, depending on whether an earth connection is fitted. You may have a hairdryer, electric razor, or other small appliance that you use regularly. Make sure that they will work here before you add them to your baggage.