For the , the border between NSW and Victoria will be closed in what will be a mammoth logistical challenge.
From 11:59pm on Tuesday, no-one from Victoria will be allowed to cross the border into NSW unless they have a valid permit.
It comes as Victoria recorded its highest daily increase of COVID-19 cases on Monday, at 127. Fifty-three cases are linked to the public housing towers outbreak in Melbourne.
Victorian Premier Daniel Andrews said the border closure decision was made in consultation with NSW Premier Gladys Berejiklian, NSW Chief Health Officer Kerry Chant and Prime Minister Scott Morrison.
"We have - all of us - agreed that the best thing to do is to close the border," Mr Andrews told reporters on Monday.
Ms Berejiklian said it was not a decision taken lightly but is necessary because of the increased rate of community transmission in Victoria, which has recorded its 20th consecutive day of double-digit growth.
"We wouldn't have taken this step unless we absolutely had to," she said.
How will the closure be enforced?
There are 55 border crossings between NSW and Victoria, with the resourcing and enforcement to be carried out by the NSW government.
NSW Police Commissioner Mick Fuller said 400 police would be deployed and barriers would be set up at popular crossing points.
He has warned of major delays for those attempting to cross the border over the next 24 hours as enforcement measures are put in place.
"We know there are four primary road crossings, 33 bridges, two waterway crossings and multiple smaller roads," he said.
"The task is not lost on me in terms of the enormity of the logistics of this operation. There are 11 local government areas and five police districts, which will all have to pull together to make sure this operation is a success."
He said he is seeking extra powers to turn people around at the border.
Drones and aerial surveillance are being used to monitor anyone trying to cross the border through the bush.
A request has also been made for Australian Defence Force resources and personnel.
What about returning NSW residents?
NSW residents who are already in Victoria can still cross the border to get home, but will need to self isolate for two weeks.
Material from the NSW government explains: "NSW residents returning from a Melbourne hotspot are already required to go into 14 days of self-isolation. This requirement will be extended to anyone returning from Victoria".
It warns those that fail to comply will face a $11,000 fine and six months in jail.
Dr Kerry Chant urged those subject to the 14-day self-isolation to ensure they .
"Self-isolation really means staying at home, minimising your contact with anyone else, and it doesn't mean going to work, engaging in any other social activities outside the house and also not permitting people into the house."
Are there any exemptions?
An online permit system via Service NSW is being rolled out over the next 72 hours to allow for exemptions for residents in border regions such as Albury-Wodonga, freight operations and other critical services.
Ms Berejiklian said anyone could apply for a permit if they "feel they will be impacted by the closure".
The permits are expected to be used mostly by those who live in a border community or who is an essential worker.![A police officer directs a car for further inspection at a check point on the Queensland-New South Wales border in Coolangatta on the Gold Coast.](https://images.sbs.com.au/drupal/news/public/qld_2_0.jpg?imwidth=1280)
![A police officer directs a car for further inspection at a check point on the Queensland-New South Wales border in Coolangatta on the Gold Coast.](https://images.sbs.com.au/drupal/news/public/qld_2_0.jpg?imwidth=1280)
A police officer directs a car for further inspection at a check point on the Queensland-New South Wales border in Coolangatta on the Gold Coast. Source: AAP
How long will the closure last?
Ms Berejiklian refused to put a firm end date on the border closure, saying the aim is for the measure to be temporary.
She said any decision to lift the closure "will be based on health advice".
Will the border closure spread to other states?
Ms Berejiklian said the border closure between NSW and Victoria is a special circumstance, and she urged other states – South Australia, Western Australia - not to close their borders with NSW.
"It's a new phenomenon, and therefore we needed to take this action," she said.
Ten new cases of COVID-19 have been recorded in NSW, all involving returned overseas travellers in hotel quarantine.
![A sign at Tomewin at the border between New South Wales and Queensland.](https://images.sbs.com.au/drupal/news/public/qld_3.jpg?imwidth=1280)
A sign at Tomewin at the border between New South Wales and Queensland. Source: AAP
Queensland Premier Annastacia Palaszczuk said she welcomed the NSW-Victoria border closure.
With just one active case in Queensland, the borders are set to open from Friday. However, visitors from Victoria will be required to undergo quarantine.
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