Scott Morrison has fully backed Queensland's decision to declare a weekend lockdown in the Greater Brisbane area following the confirmation of a case of the highly-infectious UK strain of COVID-19.
The prime minister - speaking after an emergency national cabinet meeting to discuss the UK and other variants of the virus now spreading around the world - said the situation in Brisbane was serious.
"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," Mr Morrison told reporters in Canberra on Friday.
"So it is a very wise decision by the Queensland government, by Premier Palaszczuk, to put in place the precautions she has over the next few days."
Premier Annastacia Palaszczuk said the Greater Brisbane region would be in lockdown from 6pm on Friday until 6pm on Monday after a cleaner at a quarantine hotel was diagnosed with the UK variant.
Masks will also be mandatory for those needing to go outside in this area.
"It is incredibly important in this time to stop the spread of this infectious UK strain - we must act immediately, we must act strongly and we have taken those strong measures today," the premier told reporters.
As a result of the lockdown, residents on the dole in the Greater Brisbane area are being released from their mutual obligations until January 17.
"No job seeker in the affected areas will face payment suspension or financial penalties for failing to meet their mutual obligation requirements - such as not being able to attend appointments or activities," Minister for Employment Michaelia Cash said in a statement.
Western Australia immediately introduced a hard border with Queensland from Saturday. Victoria, South Australia, Tasmania and the Northern Territory will restrict travellers from Brisbane, but NSW says it's not about to make a kneejerk response and a hard border is unlikely.
Queensland's announcement came as the national cabinet of the prime minister, premiers and first ministers held an emergency meeting by video-link to discuss the UK strain, as well as the roll-out of the coronavirus vaccine from next month.
With the UK virus and other highly contagious variants in mind, the cabinet adopted several new measures around flight travel.
These include the introduction of pre-flight testing of returning Australians, while masks will be mandatory on all domestic and international flights and airports.
International arrivals will also be reduced until February 15, rather than blocking flights from certain countries.
Mr Morrison said closing off international flights was considered at the meeting but not recommended by the national cabinet.
"Australia needs to continue to function. For example, vaccines need to come to Australia. They come here on planes, as other critical supplies do," he said.
The government is hopeful a network of vaccination hubs will be able to deliver it to four million Australians by the end of March.
The first people to be vaccinated will be quarantine and border workers, frontline health officials, aged care and disability workers and aged care residents.
Queensland reported nine new COVID-19 cases in hotel quarantine, while Victoria reported a sole case, also in quarantine.
However, NSW recorded four locally acquired cases, including one linked to the northern beaches cluster and discovered after the usual cut off period the day before.
Even so, restrictions on suburbs north of Narrabeen Bridge on the northern beaches, which have been under stay-at-home orders since before Christmas, will be lifted from Sunday.
One of the new cases is linked to the Croydon cluster in Sydney's inner west and two are linked to the Berala cluster.
There were also seven cases in returned travellers.