You can legally drive in New Zealand for up to 12 months if you have either a current driver's licence from your home country, or an International Driving Permit
All drivers, including overseas visitors, must carry their licence or permit when driving. You will only be able to drive the same types of vehicles you are licensed to drive in your home country.
Make sure your overseas driver's licence is current. If your licence is not in English, you should bring an English translation with you or obtain an International Driving Permit. Contact your local automobile club for further details about obtaining a translation or an International Driving Permit.