Passengers aged 12 and over on domestic and international flights will now be required to wear a mask under a new ruling from national cabinet.
Leaders have also agreed to pre-flight coronavirus testing for people travelling to Australia from the UK, while the number of international arrivals in NSW, Western Australia and Queensland will be halved until February 15.
The measures were given the green light by national cabinet on Friday in a bid to combat the spread of a highly contagious COVID strain that has wreaked havoc in the UK.
Scott Morrison warned it was a “false hope” the strain could be contained in Britain.
The Prime Minister welcomed Queensland’s decision to place Brisbane under a three-day lockdown after a case of the strain was confirmed in the city.
National cabinet has declared the city a COVID-19 hotspot.
“I know they will be some in Brisbane today asking why is this necessary? There is only one case. Well, this isn’t any ordinary case. This is a very special case and one that requires us to treat things quite differently until we know more,” he said.
“We need to give our contact tracers a head start to ensure that they can track down and run down all of the contacts from this individual.
“In Brisbane, we’re dealing with a different situation. There are many unknowns and uncertainties in relation to the new strain, and so that’s why this precautionary approach, we believe, is very sensible.”
Mr Morrison said the measure had the support of the federal government, the chief medical officer, and all state and territory leaders.
He urged all Brisbane residents to comply with the measures to avoid a rapid spread.
“Don’t go home to another state or any other part of your state. Over the next few days, stay where you are. If you’re somewhere else and you are planning to go there, don’t,” he said.
“This is something we can’t allow to get ahead of us … I believe this is a proportionate response to the very real risk.”
Passengers on commonwealth charter flights are already required to take a pre-flight COVID-19 test.
However, all travellers to Australia must now return a negative test result prior to departure.
Mr Morrison said there would be exemptions for people in extenuating circumstances as well as seasonal workers from “amber-risk” countries where testing is limited.
Chief medical officer Paul Kelly said the precautions were necessary, with overseas arrivals the biggest virus risk facing Australia.
“It’s a dangerous world out there. It’s become clearer now that that particular strain is more transmissible … That’s the issue,” Professor Kelly said.
“This is a moment for Australia to take notice, and as we did about a year ago, some of these drastic actions may seem like we‘re changing things rapidly.
“There’s a reason for that, there’s science behind it. It’s about keeping Australians safe.”
Mask wearing will also become mandatory in all domestic airports within Australia over the next week, but children under 12 and people with exemptions will not be required to wear them on domestic flights.
Passengers should wear masks while in international airports overseas, and international aircrew must undergo a COVID-19 test in Australia every seven days or on arrival.
Virgin said it welcomed the consistent national approach.
“Customers should ensure they’re aware of the evolving travel restrictions currently in place across Australia, including the federal government’s directive to wear face masks and coverings onboard all domestic services,” a spokesman said.
“Hand sanitiser and face masks are available for customers prior to boarding and onboard all Virgin Australia services.”
National cabinet will not be increasing the number of international repatriation flights coming into Australia.
Leaders also agreed on a new testing standard for quarantine workers, including those involved in transporting guests. Under the changes, testing will now be conducted daily instead of every seven days.
Leaders also agreed that they would now meet every fortnight, or more often, if required.
Mr Morrison said the government’s plan to roll out the COVID-19 vaccine in late February, earlier than initially scheduled, had been well received by national cabinet.
He refused to commit to extending support such as JobKeeper beyond March despite the Brisbane lockdown.