State premiers will urge Scott Morrison to speed up the schedule for booster shots after the emergence of the Omicron variant of the Covid-19 virus which has seen cases surge to record numbers in New South Wales.
Before the hastily scheduled national cabinet meeting on Wednesday, the NSW health minister, Brad Hazzard, and his Victorian counterpart, Martin Foley, wrote to Greg Hunt calling for the commonwealth to shorten the booster eligibility period.
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While most Australians are eligible for a booster shot five months after their second Covid-19 vaccine dose, the letter calls for Australia's top immunisation advice panel to fast-track the program.
Citing what they described as "a very challenging holiday and summer period" ahead, the two ministers want the Australian Technical Advisory Group on Immunisation to make "specific determinations" for the two states.
As of Friday, just over 1.51 million Australians had received a booster dose out of an eligible group of 3.16 million. There are currently 3.2m doses of mRNA vaccines at primary care and state vaccination settings, with 4.8m expected to be in clinic fridges across Australia by Christmas.
Wednesday's national cabinet meeting is scheduled to begin at midday with leaders to first receive an update from health experts about the Omicron variant before discussing the booster program interval period. They'll also receive updated Doherty Institute modelling.
On Tuesday, the acting Victorian premier, James Merlino, said the state was calling for a "shorter interval" between the doses, saying the booster should be considered as a "third dose" and that the timing should be "as short as possible".
The NSW premier, Dominic Perrottet, said he was hoping for a "constructive discussion" at national cabinet about shortening the Covid vaccine booster interval from five months to four, and said his government would do "whatever we can" to provide supports for a sped-up program.
"Because the faster we get booster shots into arms, the safer the community will be as we continue to open up here in NSW."
Guardian Australia understands the Queensland government is also supportive of a shorter booster timeframe, although the situation is less urgent in that state because of lower case numbers.
The South Australian premier, Steven Marshall, also added his name to the list of premiers pushing for booster shots to be brought forward to four months after that state recorded 154 new cases on Tuesday.
Marshall said he was keen to hear what Atagi had to say about the proposal.
"We were strongly supportive of reducing the gap between the second dose and the booster from six months down to five months. It's our belief here in SA that we should consider reducing that down again," he said.
"We would like to have a decision... we are very keen to provide the opportunity for people to get boosters sooner because we know it will increase their protection."
Masks are still required in a range of SA settings, including public transport and shared indoor spaces. SA is set to further ease restrictions on 28 December, and is still considering allowing the general public to use rapid antigen tests.
Speaking from Queensland on Tuesday, Morrison said he would leave it up to Atagi to make a decision on booster intervals.
"They are the experts when it comes to immunisation," the prime minister said, adding: "We continue to listen to them on these issues, as I have said on many occasions.
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"What I will not do is I will not front-run their advice on that issue. They will consider these issues carefully and they will advise the government. Just as they will carefully consider, as they have been for some time, the interval period for booster shots."
The national cabinet meeting comes at another key inflection point during the Covid-19 pandemic in Australia. On Tuesday NSW reported a record 3,057 new cases of the virus, with the state government facing an increasing push for the reintroduction of indoor mask mandates.
Advice from the Australian Health Protection Principal Committee, signed by the chief medical officer, Prof Paul Kelly, shows the nation's top health official supports mandates.
"Masks should be mandated in all indoor settings including retail, hospitality when not eating or drinking, and entertainment facilities," read the advice first reported by the Sydney Morning Herald.
"Implementation of mask-wearing measures should occur prior to Omicron case escalation to have maximum benefit."
Related: 'Too early to tell': health experts nervous about Omicron's effect on Australia's hospitalisation rates
On Tuesday, the Royal Australian College of Physicians added its voice to calls for indoor mask-wearing, as well as mandatory QR code check-ins at public venues and events and indoor venue capacity restrictions.
But speaking from Queensland on Tuesday, Morrison said decisions about the use of mask mandates were up to individual states, and he wanted to encourage a "culture of responsibility".
"We just need to live with this virus sensibly and practically," he said. "From mandates to responsibility and as governments around the country, because the states have the total authority when it comes to public health orders.
"The commonwealth does not have the power to direct those state and territory governments. What I will be saying to them, and I know a number of premiers agree with this, is we have got to move to the next phase of how we live with this virus. The time for that heavy hand is behind us."
Additional reporting by Elias Visontay