The Government will today consider whether to allow travel from at least some Australian states once the transtasman bubble pause ends tomorrow night.
Jacinda Ardern told Breakfast she expected the bubble would resume shortly with the exception of NSW, which was experiencing a fresh Covid-19 outbreak.
And she said Wellington would likely move to level 1 from Wednesday if there were no positive tests.
The Government paused the bubble to protect New Zealand's freedoms and to give it time to potentially put in place pre-departure tests.
Covid-19 Response Minister Chris Hipkins earlier warned things in Australia were "at their worst in quite some time".
Hipkins announced on Sunday that level 2 in Wellington would be extended for a further two days to allow more time to ensure nobody had been infected by an Australian visitor over the weekend of June 20.
He also addressed the decision on Saturday night to pause the Australian quarantine-free bubble completely for at least three days - the first time the entire bubble has halted since it began in April.
Cabinet would consider whether it would reopen the bubble, at least for some Australian states. However, he warned that things were "the worst they've been in some time" in Australia, and the rate at which the virus was spreading showed it was not yet under control.
Hipkins acknowledged it would disrupt people's plans and keep people separated.
"There are no desirable decisions here. All of them have a risk and a consequence attached to them. But the Delta variant poses a new and greater risk and we need to be very aware of that."
There were now lockdowns in Sydney and in Darwin, and Hipkins pointed to high risks it had spread further afield.
New Zealand authorities were scrambling to make sure nobody had travelled to New Zealand from a mine in the Northern Territory, where a person had worked with Covid-19 for a week.
About 900 workers had since left the mine and gone elsewhere.
Australian Medical Association New South Wales Council Dr Michael Bonning said there was a pretty high level of concern about the latest outbreak, particularly with a case emerging in Northern Territory.
He told NewstalkZB's Mike Hosking many of the New South Wales cases were linked and developing while in quarantine.
Unfortunately, the Delta variant had forced a lockdown coupled with a slow vaccine rollout.
"But certainly we're seeing a problem of our vaccine rollout system that it hasn't relied on the whole health care system," he said.
Director-general of health Dr Ashley Bloomfield also announced an order to require anybody who had been in Sydney since June 21 and now returned to act as if they were still in Sydney - and stay away from others.
Air New Zealand has now cancelled all passenger flights from Australia to New Zealand during that pause until Wednesday morning, and reduced flights from New Zealand to Australia.
Cabinet would consider whether New Zealand should reopen for states in Australia that do not have cases, and was likely to bring in pre-departure testing.
Covid-19 modeller Professor Michael Plank said the Government was right to take a cautious stand while the Delta variant spread in Australia.
"If there is even one case lurking out there, it has the potential to spread like wildfire because the Delta variant is so infectious and our vaccination coverage is too low at the moment to slow it down much."
The move to pause quarantine-free travel from Australia has concerned tourism and travel operators who were hoping for an influx of visitors for the ski season when the Australian school holidays start in a week.
Hospitality New Zealand chief executive Helen White said the pause had already resulted in cancellations of bookings.
"This is a kick in the guts for operators. We appreciate we need to manage the health risk, however this comes at a cost and our sector is at the brunt on this cost."
She said it showed how crucial it was for the vaccinations rollout to ramp up. "That should be given top priority over everything else the Government is doing right now."
On the decision to keep Wellington at level 2 for a further 48 hours, Hipkins said so far all but 300 of the 2400 contacts had returned a test result, and all so far had been negative.
However, he said the man's partner who travelled with him had now tested positive after initially testing negative.
Hipkins urged people to double-check the locations of interest to make sure they had not visited them, given it showed the man could transmit the virus and was likely infectious at the tail end of his stay.
That was particularly important for Sunday June 20, when the man visited One Red Dog, and the Countdown on Cable Lane on the Sunday, and Monday morning at Wellington Airport.
He also urged anyone with cold or flu symptoms to get a test, saying daily test numbers were low and it was needed to be certain there was no undetected community spread.
Wellington Mayor Andy Foster said it was responsible to extend level 2. While businesses were affected, it had been a "huge relief" that so far there had not been a need to scale upwards into a more stringent lockdown, he said.
Otago University epidemiologist Professor Nick Wilson said the extension in Wellington was wise, and a "very strong case" for adopting a period of pre-departure testing, which could be combined with testing on arrival in New Zealand, once quarantine-free travel with Australia reopened.
Act leader David Seymour said the complete pause of the bubble showed New Zealand's Covid-19 response – especially the vaccination rollout - had not developed enough.
"Lock 'em down and lock 'em out remains the Government's only response to outbreaks.
"Next week three states that have closed their borders to infected states go on school holidays. Will the Government deny the tourism industry those dollars for no good reason?"
Hipkins said there was already public nervousness about the bubble – pointing to research by the Covid team in the Department of Prime Minister and Cabinet which showed New Zealanders were more nervous of the Australia bubble than the Cook Islands bubble, and were opposed to opening up to more countries.
