The rule is short: the NZeTA is attached electronically to the passport used in the request, and you must travel on that passport. Everything else follows from that.
Choosing which passport
- It must be a passport from a visa-waiver country or territory — otherwise the NZeTA is not available on that document
- If only one of your passports is eligible, that is the one to use
- If both are eligible, use the one you will actually be carrying and checking in with
Where it goes wrong
Dual nationals are refused boarding for this more often than for any problem with the authorisation itself. The airline checks the passport in your hand against the record. If the NZeTA is attached to your other passport, the system finds nothing, and nothing is what the check-in agent acts on.
If you renew one of them
A new passport means a new NZeTA, even though the authorisation would otherwise last 2 years. This applies to whichever passport the NZeTA is attached to.
New Zealand citizens
If one of your nationalities is New Zealand, you travel on your New Zealand passport and do not need an NZeTA at all. Requesting one on your other passport does not change that.
Source: Immigration New Zealand — NZeTA
More on the NZeTA
What is the NZeTA
The NZeTA is a pre-travel authorisation for visa-waiver passports, not a visa. What it covers, who needs one, and what it does not do.
How to apply
Applying takes about ten minutes in the official app (NZ$17) or on the Immigration New Zealand website (NZ$23). Here is the order of the steps and what trips people up.
Cost
The NZeTA request fee is NZ$17 in the app or NZ$23 online, plus the NZ$100 IVL — about NZ$117–NZ$123 in total.
What you need
A valid passport, a photo of your face, an email address and a payment card. What the photo has to look like and what else is asked.
Processing time
Most NZeTA requests are decided in minutes, but Immigration New Zealand asks you to allow up to 72 hours. What makes an application take longer.
Validity
An NZeTA lasts 2 years from the date it is issued, or until your passport expires — whichever comes first — and allows multiple entries.