A Covid-19 flare-up in South Australia shows why it's important New Zealand hasn't rushed into looser transtasman travel arrangements, Prime Minister Jacinda Ardern says.
A cluster in the state has swelled from three cases yesterday to 17 this morning - casting doubt on moves to reopen Australia's internal borders by Christmas, only days after the plans were announced.
The outbreak triggered warnings and closures across Adelaide, and was now sparking panic interstate, with Western Australia Premier Mark McGowan making a snap decision requiring anyone entering from South Australia to go into mandatory hotel quarantine for 14 days.
Queensland was now the latest jurisdiction to follow suit and announce they too will be closing off the border to parts of South Australia from midnight tonight.
Australia has earlier indicated it wants a "hotspot" regime for travel between states - where borders weren't closed until there were as many as 10 or more daily cases over three days.
While New Zealand health officials have been exploring how quarantine-free travel with Australia might work, Ardern has signalled the hotspot regime could prove too risky for our country.
Speaking to media today, Ardern said: "For me, what's happening in South Australia only further reinforces the importance of having that good understanding of how Australia intends to manage their internal borders when there are outbreaks.
"Because of course, if they have an outbreak, but they have been instituting strong border controls, then it's manageable.
"But if they have a tolerance level for community transmission that's higher than ours, then that is problematic. So those are still issues that we are working through."
She said it was important to ensure there was a good understanding of what protocols there were between each state.
"But I think what it underscores is why it's so important that New Zealand has not rushed into this," she said.
"They've had a very prolonged period of being very, very successful, but they are experiencing the reality that we all have, that, from time to time, you have cases.
"So it's just a matter of us understanding well how that's managed and making a risk assessment.
"We have a very low tolerance for risk... we currently have good economic freedom because of that."
Ardern has previously said she hoped to have some sort of transtransman travel arrangements in place by the end of the year - but there was no indication of imminent two-way, quarantine-free travel, as some Australian media have recently claimed.
New Zealand's borders have been closed to international travel since March, except for returning New Zealanders and exemptions for health workers and some key industries.
In September, New South Wales and the Northern Territory started accepting travellers from New Zealand without requiring them to quarantine.
But that is a one-way arrangement. Kiwis returning to New Zealand still need to do their 14-day stint in managed isolation. And Australian tourists are not able to travel to New Zealand.
- Additional reporting: news.com.au