Jacinda Ardern says the plan to have a two-way travel bubble with Australia by April has changed slightly given the reaction to recent cases in New Zealand and across the ditch.
In mid-December, the Prime Minister said Cabinet had agreed to establish a quarantine-free bubble by April.
But she said on Tuesday that given the recent outbreak of COVID-19 in Sydney and Australia's response to briefly suspend quarantine-free travel after there was a case in Northland connected to the border, "things have changed a bit" since she set the goal to have borders open by April.
"With any bubble arrangement, we'd want protocols in place so that there's some predictability. If we have scenario A, the reaction of either country will be aligned with scenario A," she said, referring to Australia's recent border response to New Zealand.
"We are having to go back and just check with those recent incidents that all of the activities of the different states, or indeed the reaction to us, is in keeping with what we've been working to."
But when Ardern was asked if she was expecting perfection in order to open a bubble, she denied this and said occurrences, like cases connected to the border, will happen.
"They don't happen a huge amount, but they will happen. And you ask what's wrong with that. Well, I would say the knock-on effect of that, for what was in our view something that could be managed well within our borders, the knock-on effect of that is quite significant from a commercial perspective. We have to ask the question whether or not airlines will want to operate in an environment where within three hours they can have cancellations for multiple days," she said.
"If you turn off the ability for people to come home and strand hundreds of people overseas, we then have to make a decision whether or not that closure is significant enough that when they return, do we require them all to go into MIQ because our capacity would not be sufficient to contain them. Will New Zealanders be happy if hundreds of them isolate at home if they've come from an outbreak area? It's not a simple issue to resolve, but it needs to be."
She added she didn't believe it was particularly easy for Air New Zealand to manage the cancelled flights when Australia announced it was closing the borders.
She said while one perspective is that opening the borders is a "simple matter", this isn't the case since New Zealand follows an elimination strategy.
"When you've opened up to every state and if they have an outbreak in one area, our ability to control people moving into the state and flying back to New Zealand is very limited. They're not our borders," Ardern said.
"So I do not apologise for a moment for being cautious about this. You cannot unscramble the egg. Once they're open, we have to make sure that we can make it work, because it will be damaging economically if we open, close, open, close, and then permanently shut it. No one wants that."
The other travel bubble arrangement New Zealand has is with the Cook Islands. Currently, people arriving in New Zealand from there don't have to quarantine.
This rule has been in place since January 21 but doesn't apply to people travelling to the Cook Islands.
Those wanting to do that are only eligible if they meet a set of health and travel conditions designed to eliminate the chance of them carrying COVID-19.