A "new phenomena" in Australia's COVID-19 crisis which is now occurring throughout greater Melbourne has prompted the NSW Premier Gladys Berejiklian to backflip on her views about state border closures.
Detailing how the border closure will work when it comes into force at 11.59pm on Tuesday, Ms Berejiklian - who previously opposed border closures - said she had no problem changing her views.
"What is happening now in Victoria is very different, all of the cases are from community transmission, this is unprecedented in Australia," she said.
"When NSW had the record number of cases in Australia back in March, they were a majority from overseas. What is occurring in Victorian has not yet occurred anywhere in Australia, so it needs a new type of response."
She said police and health officials were already stationed at the state's border, stopping anybody from Victorian hotspots coming to NSW.
"Come midnight tonight, the hotspots will extend the all of Melbourne, and come midnight tomorrow it will be all Victorians," she said.
She said border communities, like Albury-Wodonga and Eden, were in for a "tough couple of days", and would not be able to move around their towns as normal until a permit systems being set up by Service NSW was in place.
"I appreciate the next 72 hours will be difficult for our border communities," she said.
As the closure comes into force, she said there would still be some train services and flights available, "but only for those who have permits and who are returning NSW residents".
Additionally, those needed access to "critical health care" within border towns would be able to access hospitals when needed.
Ms Berejiklian said she did not know how long the border closure would be in place, as it would depend on the spread of the virus.
"I'm not going to put a time limit on it, it will really come down to the health advice," she said.
NSW Health Minister Brad Hazzard said the border closure had been under consideration for some time, with officials trying to strike balance between health issues for residents and the economy.
With 127 coronavirus cases recorded overnight in Victoria, Mr Hazzard said said NSW Chief Health Officer Dr Kerry Chant had "conveyed her team's view that we had to take further steps to safeguard NSW".
"Our concern is that this seems to be spreading through the city of Melbourne, and we do have concerns that it may spread beyond Melbourne," he said.
"The borders shutting should send a vey clear message to all NSW residents that if you're thinking of going to Victoria in next 24 hours, the clear message is don't."
Dr Chant said she "felt we needed to get ahead of the potential spread" and continued to stress that all residents should keep presenting for testing, even with mild symptoms, regardless of where they had travelled..
Police Comissioner Mick Fuller detailed the a mass police effort which will be used to keep the borders under control, adding that he would call in the Australian Defence Force for help.
He said the operation would mostly focus on the four main highway crossings and other roads, but that police would use drones and other "24/7 aerial patrols" to keep more remote areas of the border in check.
He added there was still an $11,000 fine and possible six months jail for people trying to travel in NSW from hot spots in Victoria.
This would extend the all Victorians from 11.59pm on Tuesday," he said.
The decision to close the border was made jointly by Victorian Premier Daniel Andrews, Prime Minister Scott Morrison and NSW Premier Gladys Berejiklian.