"Immigration New Zealand is introducing a new travel requirement for visitors from visa waiver countries from 1 October 2019.
It’s called the NZeTA (New Zealand Electronic Travel Authority). All visitors - whether they're coming for a holiday, to visit friends and relations,
or to study for a short time - who are eligible to travel to New Zealand without a visa will need to hold an NZeTA before they board their flight or cruise from 1 October 2019."

Thanks for the info Diamantina. It's not terribly clear if Australian passport holders need to apply for this. Australia is not on the visa waiver country list. But it says if travellers are leaving after 1 Oct 2019 they need to apply. Is that only if you are from a country on the visa waiver list? (Is it just me? )

Kay

The information on that NZ govt. webpage is not well-written. I'm confused, too. Luckily, the link on the New Zealand website is clear:
"Traveling on a New Zealand or Australian passport? You don't need a visa or NZeTA to enter New Zealand."

Yes, as far as I can tell, citizens from visa waiver countries will need NZeTAs as of Oct. 1, unless they also hold NZ or Australian passports. Citizens of visa waiver or transit visa waiver countries just transiting through NZ will also need NZeTAs.
But the NZeTA will be good for multiple entries (of up to three months) over two years. The Australian ETA is valid for multiple entries for just one year.

Sorry, I meant to write, "Luckily, the link on the Air New Zealand website is clear."

Note that most visitors will have to pay about NZ $45 for this, which is another new requirement.