Residents of greater Sydney have again found themselves isolated, as every state and territory moves to lock them out after a COVID-19 cluster on the city's northern beaches ballooned to 70 cases.
Meetings of the nation's health ministers on Saturday and Sunday prompted announcements from premiers determined to prevent the virus jumping borders.
WA Premier Mark McGowan led the pack on Saturday, reimposing a "hard" border with all travellers from NSW.
Only those with exemptions - such as essential health and freight workers - are allowed into the state.
On Sunday, Victoria declared greater Sydney and the Central Coast a red zone, shutting them out too.
South Australia, Queensland, the Northern Territory and the ACT then followed.
People travelling from the hotspots will not be able to enter the jurisdictions from Monday.
If they do enter, they will have to undergo 14 days of hotel quarantine in most states, or quarantine at home in South Australia and the ACT.
Only those from greater Sydney will have to quarantine for two weeks on arrival in Tasmania.
Greater Sydney stretches from the Hawkesbury, Hornsby and northern beaches regions in the north, to the Blue Mountains in the west, and the Wollondilly, Campbelltown and Sutherland regions in the south.
Those who have been in the Wollongong local government area also cannot enter SA, while the NT, ACT, and Queensland have barred the entire Illawarra/Shoalhaven region.
Victorians can quarantine for 14 days at home if they return before midnight Monday.
Returning Queenslanders are offered the same deal until 1am Tuesday.
Acting Chief Medical Officer Paul Kelly on Sunday defended the way states and territories responded, while offering his sympathy to Sydneysiders facing the prospect of Christmas alone.
"Talking to my colleagues in other states, they are taking a very proportionate approach to this using that hotspot definition," he told reporters.
"It's unfortunate that this is happening but we need to put safety and health concerns at the forefront.
"Those on the northern beaches of Sydney, my heart goes out to you. This is a tricky time in the lead-up to Christmas but please stay the course."
The NSW outbreak grew by 30 cases to 70 on Sunday, with Premier Gladys Berejiklian saying "the one positive is we still have not seen evidence of massive seeding outside the northern beaches community and our aim, of course, is to keep that in place".
The state government also beefed up its own restrictions for greater Sydney, which will remain in place until 11.59pm on Wednesday.
No more than 10 people are allowed at household gatherings and patrons will need to maintain a four-square metre distancing at venues.
Up to 300 people will be permitted at places of worship and hospitality venue attendance, while singing and chanting at indoor venues is banned and dance floors will only be allowed at weddings.
Northern beaches residents are currently under strict stay-at-home orders until Wednesday.
Meanwhile, the Sydney to Hobart Yacht Race, scheduled to begin on Boxing Day, has been cancelled because of the Tasmanian restrictions on visitors from NSW.
