The federal government announced that people returning to Australia would be required to test negative for COVID-19 pre-flight on Friday.
“The idea that it somehow can be contained just out of the United Kingdom is a false hope,” Morrison said.
“It moves so quickly, far more quickly, than previous strains of the virus,” he said.
The National Cabinet met on Friday and agreed to the new measures in relation to quarantine and flights to reduce the risk of exposure to the new strain.
There will be exemptions and “tailored responses” in extenuating circumstances, such as seasonal workers from low-risk countries—mostly in the Pacific—where there is limited access to testing.
Passengers and aircrew will be required to wear masks onboard international flights, with the crew also wearing other personal protective equipment where appropriate.
Masks will also need to be worn while in an international or domestic airport environment.
International aircrew must undergo a COVID-19 test in Australia every seven days, or on arrival, and will need to quarantine in a dedicated quarantine facilities between international flights or 14 days, Morrison said.
The national cabinet also agreed that for domestic travel, mask-wearing would be mandatory on all domestic flights excluding children under 12 and those with other exemptions.
The leaders also agreed to slow down international arrivals until Feb. 15.
In New South Wales, Western Australia, and Queensland arrivals will reduce by 50 percent, but in Victoria (which already operates at less than 50 percent) and SA there will be no change.
The ACT, Northern Territory, and Tasmania will continue their bespoke arrangements.
Government-chartered flights will continue.
“With our chartered flights, we have total control of who gets on the plane,” Morrison said. “So we can ensure that it is vulnerable people who get on those flights ... or a family member of that vulnerable person.”
Chief Medical Officer Paul Kelly said the testing regime was another ring of containment, but it was not foolproof.
Professor Kelly said he was aware of 15 people who tested positive being denied access to a recent government charter flight.
Morrison said the lower caps would have consequences in terms of Australian trade and business and engagement with the rest of the world.
“There are no consequence-free decisions here, and so it is about managing the risk as appropriately and as proportionately as possible,” he said.
National Cabinet also discussed the possibility of targeting bans on travel from specific countries but rejected it.
“The idea that you can somehow narrow-stream your response here and mitigate the risk just dealing with one channel into Australia is not true,” Morrison said.