As Australian authorities scramble to get on top of a new, more contagious mutation of the coronavirus, coming out of the UK, the number of incoming international travellers will be temporarily halved.
NSW will slash the number of international arrivals it will accept to 1505 per week. In Western Australia, international arrivals will be reduced to 512, while in Queensland the number will fall to 500. The caps will be raised again on February 15.
Under the new rules agreed to by national cabinet, masks would be made mandatory on all domestic and international flights.
Inbound travellers to Australia must now be tested for COVID-19 before getting on a plane. Anyone who tests positive themselves or has a household contact who tests positive while overseas will not be allowed onto a plane headed for Australia.
All workers involved in the quarantine process, including cleaners, transport workers, medical staff and more, will now be subject to daily testing nationally. They had previously been required to get tested once a week.
Brisbane was plunged into a three-day lockdown from 6pm on Friday after a quarantine hotel cleaner tested positive to the new virus strain. Prime Minister Scott Morrison said the situation in Brisbane was "serious".
"Yes, we know there is only one case. But what we do know is that this new strain is some 70 per cent more transmissible than the previous strains of the virus," he said. "We anticipate that this will become the more dominant strain of the virus globally.
"It moves so quickly - far more quickly than previous strains of the virus - and that means we need to give our contact tracers that head start."
Chief medical officer Paul Kelly said the way Australia had fought the virus in the past would be less effective if this strain got a foothold in the country.
"Our main issue is to keep Australians safe and to really make sure that this particular strain is not the one that becomes circulating in Australia," Professor Kelly said.
"The reason is because it will be much more difficult to control. All of the things we've done in the past, all of those controls we've talked about in terms of test, trace, isolate - all of those personal measures, even some of the other measures we've had to do in certain times during this pandemic, will become less effective if this virus was to establish itself in Australia. So that's why we're going hard and fast and strong."
The Australian Health Protection Principal Committee did consider stopping flights in response to the UK strain, Mr Morrison confirmed. However, he said it was not feasible, or medically advisable, to shut Australia off from the world and ban all flights into the country. For Australia to be able to function, he said, supplies needed to be able to be brought in, including vaccines.
Mr Morrison also said 80 per cent of Australians currently registered overseas were in countries where the UK coronavirus strain had been recorded.
Meanwhile the Greater Brisbane area has been declared a Commonwealth COVID-19 hotspot, while the ACT, Tasmania, and the Northern Territory will require people who've entered from Brisbane since January 2 to undergo 14 days of quarantine.
Western Australia has also brought back the hard border with Queensland.
Professor Kelly warned anyone who had been in the Greater Brisbane area since January 2 that they should assume the restrictions in Brisbane now applied to them. They should isolate, get tested and watch for any symptoms.
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