Take out travel insurance. Your policy should cover any activities you plan to undertake (from scuba diving to scooter riding), personal liability, medical treatment, emergency medical evacuation, and any pre-existing medical conditions. Even minor medical treatment can be very expensive overseas.
If you suffer an injury overseas and return to New Zealand, ACC may be able to help with treatment costs in New Zealand, but only if you intended to be overseas for less than six months. ACC is unable to cover expenses incurred overseas. Visit www.acc.co.nz/travel to learn more.