From October 1st, 2019, foreign visitors, as well as travelers transiting New Zealand, must obtain an Electronic Travel Authorization (NZeTA) before entering New Zealand.
If you plan to visit New Zealand for vacation, you will need to get a New Zealand ETA or a visitor visa.
Nationals from Visa Waiver countries planning to visit New Zealand for touristic purposes do not need a visitor visa, they can apply for a New Zealand ETA online.
If you are a citizen of Australia you do not need a visa to enter New Zealand on your Australian passport, however, if you are an Australian permanent resident you must apply for a New Zealand ETA.
The NZeTA is not a visa and does not guarantee entry to the country. Upon arriving in New Zealand, travelers must comply with all entry requirements, for example, owning a ticket for a subsequent trip, enough money to live while in NZ and etc.
Travelers who are in the process of obtaining a visa to New Zealand do not need to apply for NZeTA, they must only hold a valid travel document.
Travelers who have permanent residence or New Zealand citizenship do not need an ETA or a visa to enter New Zealand.