An outbreak of the highly contagious UK variant of COVID-19 in a Queensland quarantine hotel has grown to six cases, Premier Annastacia Palaszczuk has said.
Victorian and NSW health authorities have released urgent advice for returned travellers or staff members who attended a quarantine hotel in Brisbane linked to the UK COVID-19 variant.
Late on Wednesday, Victoria's health department implored anyone in the state who quarantined or worked at the Grand Chancellor hotel on or after 30 December to isolate and contact the coronavirus hotline immediately.
NSW health authorities released a similar alert, asking anyone who has been at the hotel since 30 December, either as a returned traveller or as a staff member, to get tested immediately and isolate for 14 days after they were last there - regardless of their test result.
Those people should also get in touch with NSW Health by phone for further advice.
Speaking to Sunrise on Thursday morning, NSW Premier Gladys Berejiklian said the variant can't be "prevented" from entering Australia.
"What we have to be real about is that we’re not going to be able to keep it out so long as we’re welcoming Aussies back to Australia,” Ms Berejiklian said.
“We have to assume those more virulent, more contagious strains are going to be in quarantine.
“We can’t stop that, we have to be honest and upfront about that.”
The warning came as the Brisbane hotel was shut for deep cleaning after six people - four quarantining guests, a cleaner and her partner - contracted the highly contagious UK coronavirus variant.
Premier Annastacia Palaszczuk on Wednesday said all six cases in the COVID-19 cluster, who are in isolation, were on the seventh floor of the Brisbane hotel at different times during quarantine.
All 129 people quarantining at the hotel will now be moved to another hotel and tested, while 226 people who have worked at the hotel since 30 December will be isolated and tested.
"The Queensland government has notified NSW Health there are NSW people staying at the hotel who have since returned to NSW," NSW Health said.
"NSW Health is working with Queensland Health to identify these people so our contact tracers can provide public health advice and updated information as it becomes available."
State government defends Victorian travel permit system
Travel from the "red zones" of Greater Brisbane and Greater Sydney remains banned, with the state government defending its tough border restrictions.
While the state has reopened its border to regional NSW, thousands of Victorians have been stranded in Greater Sydney for almost two weeks.
Under the "traffic light" system, anyone coming into Victoria from interstate must apply for a permit, with those entering from "orange" zones such as regional NSW required to be tested within 72 hours of their return.
Only those who receive an exemption from the health department can enter from a "red" zone.
Almost 83,000 people have been issued permits since the system launched on Monday, some three hours later than planned due to a technical issue.
Government ministers Luke Donnellan and Martin Pakula defended the system at separate press conferences on Wednesday.
Mr Donnellan said the border restrictions were based on public health advice and took into consideration the number of active cases in a state as well as mystery cases.
"What may appear to be brutal and uncaring and the like is very much done with the interests of the Victorian public at heart to ensure we don't have another situation where we have to lock down," Mr Donnellan said.
"The idea of just saying let everything rip and then we'll just deal with the consequences again, I don't think the Victorian public wants (that)."
He said there was "no way known" the government would change its approach to managing the virus because people were "getting grumpy".
Mr Pakula, meanwhile, said Victorians interstate and overseas will be able to return home "bit-by-bit".
He defended the decision to allow 1200 tennis players and their support staff to enter the state from Thursday, ahead of the Australian Open starting on 8 February.
All will be required to quarantine at one of three hotels for two weeks, although each player and one support person will be permitted to leave their rooms for training and treatment.
They will be tested daily for COVID-19.
"We have a responsibility to bring people home - and we are - and we also have a responsibility to protect our incredible major events calendar and to protect the state economy," Mr Pakula told reporters.
"It's not all one and not the other."
But the Australian Formula One Grand Prix will not go ahead as planned in March.
Victoria recorded a full week without a local or interstate-acquired coronavirus case on Wednesday, with three new infections detected in hotel quarantine.
People in Australia must stay at least 1.5 metres away from others. Check your jurisdiction's restrictions on gathering limits.
If you are experiencing cold or flu symptoms, stay home and arrange a test by calling your doctor or contact the Coronavirus Health Information Hotline on 1800 020 080. News and information is available in 63 languages at sbs.com.au/coronavirus.