The travel bubble between New Zealand and Australia could be in jeopardy.
Doubt is being cast over the arrangement, given the recent re-emergence of Covid-19 in Sydney's northern beaches community and the new, more infectious strain of virus spreading through the UK.
Herald Senior Politics Writer Claire Trevett told Newstalk ZB's Francesca Rudkin she can't see a travel bubble being in place before a vaccine is available here.
"I don't know if the Prime Minister would be willing to jeopardise the progress we've made for a bubble a few months before a vaccine arrives."
New Zealand has agreed to establish a travel bubble with Australia in the first quarter of 2021 - or had, before the latest breakout across the Tasman.
The latest cluster in Sydney's Northern Beaches now has 68 cases after 30 more were reported overnight, and that area has been put in lockdown until Wednesday.
From today, the neighbouring state of Queensland is requiring arrivals to have a border pass and get tested for the coronavirus.
Tasmania requires anyone coming from the state to spend 14 days in quarantine - but anyone who has been in Sydney's Northern Beaches is banned.
Western Australia is reimposing its hard border, so no-one can travel there from New South Wales.
WA's Premier Mark McGowan said while he regrets having to take the step less than a week before Christmas, the risk of Covid-19 emerging in the community is too high.
"I know these changes are going to be hard to take for many people," McGowan said at a press conference last night.
"I know it will throw Christmas and reunion plans into disarray if it hasn't already.
"These are now extraordinary circumstances.
"I wish I didn't have to be making this announcement but as Premier I have a responsibility for every Western Australian and I need to do what is right to keep our state safe and strong."
McGowan said it was not known how long the border would stay up.
"We hope it's only for a short period and we can reassess our border controls when the health advice says it's ok to do so," he said.
He advised West Australians to reconsider travel to New South Wales.
"WA's community has been Covid-free 252 days. I want to keep it that way," he said.
"I want to protect people's health and, in turn, protect people's jobs.
"If you can avoid it, please don't go."
NZ monitoring situation in NSW
The New Zealand government says it is monitoring the new Covid-19 cluster in Sydney closely but it is too early to say if it will affect a trans-Tasman bubble.
"As previously stated, a travel bubble won't start until the first quarter of 2021," a government spokesperson said in a statement.
"Commencement is dependent on no significant change in the circumstances of either country.
"Decisions on whether or not to proceed with a travel bubble will occur in the new year and we will assess the situation at that point.
"We're monitoring the situation closely, but it's too early to make any decisions based on the current community cases in New South Wales."
Very few exemptions expected
McGowan said very few people would be eligible for an exemption to travel from New South Wales to Western Australia.
However, some may be granted entry on compassionate grounds, including people who had travelled to NSW recently and needed to come home.
"It's pretty tough," McGowan said.
"But imagine us having to shutdown Perth or Margaret River or Bunbury or Broome over Christmas.
"That's what we're trying to avoid here."
Some senior government officials, active military personnel and truck drivers are among those who will still be able to travel between the two states.
All 68 people who had been in the Sydney Northern Beaches area before travelling to WA have tested negative for the virus.
Second NSW travel change in two days
The announcement comes just hours after the WA Health Minister Roger Cook held a media conference painting a much more positive picture of the border situation.
"At this stage we don't, at this point in time, see the need to go further than the current arrangements we have," Cook told a midday press briefing.
However, he acknowledged the situation was unpredictable and "could change at any time".
The hard border replaces the arrangement in place since Thursday requiring travellers from NSW to self-isolate upon arrival in WA.
WA recorded one new Covid-19 case overnight - a man in his 30s who had arrived from overseas and remains in hotel quarantine.
The returned traveller brings WA's total Covid-19 case number to 845, including 14 active cases.
It's been 252 days since community transmission in WA.
With reporting by RNZ