Sydney's Northern Beaches area has been declared a national coronavirus hotspot, allowing the region to get extra support for personal protective equipment, contact tracing and resources for aged care facilities.
The Northern Beaches cluster has grown to 28 cases, two days after the first infections emerged.
It’s the first time a national hotspot has been declared by the Commonwealth with the coming days critical in curbing the spread.
However Christmas plans have already been thrown into disarray as a number of states and territories impose new rules on NSW.
Victorians have been urged not to travel to Sydney and warned they could face 14 days quarantine should they do so and want to return.
From midnight on Friday, a permit system will be in place for NSW residents entering Victoria.
Western Australia has reintroduced a 14-day quarantine requirement for all NSW travellers, while anyone who has entered the state from NSW since December 11 also has to self-isolate.
WA leader Mark McGowan said he would not hesitate re-introducing a hard border with NSW should the health advice recommend it.
"We are very concerned there will be many more community cases in NSW," Mr McGowan said in a statement.
Queensland police will be meeting all flights arriving into the state, with travellers from Sydney's Northern Beaches told to quarantine at home for two weeks from when they were at a hotspot.
But from 1am on Saturday, anyone arriving in Queensland from Sydney's Northern Beaches will face mandatory hotel quarantine for 14 days, but the NSW border will stay open.
"At this stage we will continue to observe that hotspot regime and that has been consistently followed throughout Australia as well," Premier Annastacia Palaszczuk told reporters on Friday.
"I just want to give people that sense of security ... We are following practices that other states and territories are also [doing] at this stage. So I just want to alleviate people's concerns there."
Anyone who enters the ACT and has been on Sydney's Northern Beaches since December 11 must get tested and self-isolate.
Anyone in South Australia who recently arrived from NSW should self-isolate for 14 days and get tested if they have visited venues on NSW’s health alert list.
South Australian authorities are "watching closely" the COVID-19 outbreak in Sydney but remain confident contact tracing will identify the source of the infections.
"It's a stark reminder to everyone that even though we've effectively eliminated Covid-19 from within our communities, it can find it's way back in," SA Police Commissioner Grant Stevens reporters on Thursday.
"We need to be in a position to respond quickly if that does occur."
The Northern Territory has declared Sydney's Northern Beaches a coronavirus hotspot, forcing anyone from that area into 14-days of supervised quarantine in Darwin.
People in the NT who visited Sydney's Northern Beaches since December 11 are also being asked to self-isolate immediately and get tested and remain in isolation until their tests results are known.
Anyone who has visited the Northern Beaches Council area since December 11, as well as the Kirribilli Club, Penrith RSL and Gannons Park in Peakhurst at various times between December 11 and December 14, is barred from entering Tasmania.
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