Whether or not you need an eTA to visit New Zealand will depend on the country you are from.
Travellers from visa-waiver countries can obtain a New Zealand eTA to visit. You won’t need a visa in this case can can travel solely with an eTA.
The following countries can obtain a New Zealand eTA:
Andorra, Argentina, Austria, Bahrain, Belgium, Brazil, Brunei, Bulgaria, Canada, Chile, Croatia, Cyprus, Czech Republic, Denmark, Estonia (citizens only), Finland, France, Germany, Greece, Hong Kong (residents with HKSAR or British National–Overseas passports only), Hungary, Iceland, Ireland, Israel, Italy, Japan, South Korea, Kuwait, Latvia (citizens only), Liechtenstein, Lithuania (citizens only), Luxembourg, Macau (only for Macau SAR passport holders), Malaysia, Malta, Mauritius, Mexico, Monaco, Netherlands, Norway, Oman, Poland, Portugal (if you have the right to live permanently in Portugal), Qatar, Romania, San Marino, Saudi Arabia, Seychelles, Singapore, Slovak Republic, Slovenia, Spain, Sweden, Switzerland, Taiwan (if you are a permanent resident), United Arab Emirates, UK (for UK passport holders with permanent residency only), USA (including USA nationals), Uruguay, Vatican City.