The National Cabinet has approved pre-flight testing requirements for anyone travelling to Australia as well as mandatory mask wearing on all international and domestic flights, according to South Australian Premier Steven Marshall.
"Our suggestion for pre-flight testing has now been adopted by the National cabinet," Premier Marshall said.
"Secondly, we have now adopted a new national standard with regards to the wearing of masks on international and domestic flights. This previously was on advice people should wear them; it is now people must wear them."
In a later press conference, Prime Minister Scott Morrison clarified the mask rule would however not apply to children aged 12 or under.
The PM also added international flight arrival caps would be cut in half for NSW, QLD and WA.
Premier Marshall noted Queensland Premier Annastacia Palaszczuk had called out for other states to declare Greater Brisbane a hotspot, and the National Cabinet agreed to this on an Australia-wide basis.
The Northern Territory and Tasmania announced their measures for travellers from the concerned Queensland LGAs today, meaning anyone who arrives from today has to enter quarantine.
South Australia has given a little bit more leeway with a cut-off for midnight tonight, although the state's government has strongly discouraged travel from any Queensland residents.
How significant is this new highly virulent UK COVID strain?
The UK strain of COVID-19, which has been the cause of today's drastic containment measures both in Queensland and around the country towards people who have been in Greater Brisbane, was described by the Prime Minister as 70 per cent more transmissible than the previous strains of the virus.
"This strain is likely to become in the very near future, the dominant strain," Prime Minister Morrison said.
"So the idea that it somehow can be contained just out of the United Kingdom is a false hope...80 per cent of Australians looking to come back are in countries that have had exposure to that strain of the virus.
"It is a very wise decision by the Queensland Government, by Premier Palaszczuk, to put in place the precaution she has over the next few days. 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 to ensure they can track down and run down all the contacts from this individual."
The Independent Sage, a group of scientists in the UK, issued a statement last week concluded the new strain of COVID-19 that seems to have emerged in the southeast of England is between 40-80 per cent more transmissible than earlier variants.
The scientists said COVID-19 was "out of control" in the UK with current Tier 4 stay-at-home restrictions now unable to contain its spread, even with closure of schools and universities.
"The pandemic is now out of control, and the NHS is struggling, with some hospitals having to stop non-COVID activities. The NHS (National Health Service) is no longer being protected," the Independent Sage commented.
"For these reasons, there is a strong argument for maximising the coverage of the population with at least one dose of vaccine, even though this requires a change to the dosage schedule.
"The urgency of concerted and effective action to supress the new variant cannot be overstated."
The Independent Sage also called for restricted movement from and to Great Britain with the rest of the world. There are currently at least 40 nations worldwide that have closed their borders to UK arrivals, including Singapore, Spain, Canada and India.
Updated at 12:56pm AEDT on 8 January 2021.