The experts at the nation's vaccine advisory body are expected to recommend anyone older than 50 receive a fourth dose of the COVID- 19 vaccine.
It is not yet clear how much guidance will be given to those aged 30 to 49, with internal discussion about permitting a fourth dose but not specifically recommending it.
The Australian Technical Advisory Group on Immunization ATAGI will deliver its advice to the federal government soon.
The ABC has spoken with two people familiar with discussions who are not allowed to speak publicly.
The expected changes follow strong messages from politicians at a state and federal level who made it clear that they would support the fourth dose being offered to more age groups.
Federal Health Minister Mark Butler said there was a strong case for Australians under 65 to get the booster shot but said there was an open question about whether young, healthy people needed it.
Earlier this week, NSW Health Minister Brad Hazzard said he would back a general expansion of the vaccine rollout, while Victorian Premier Daniel Andrews urged the fourth shots be given to healthcare workers.
On Wednesday, Prime Minister Anthony Albanese said that he had urged health experts to work quickly on issues relating to COVID - 19, including vaccines.
When I met with the health authorities, including the CMO, I encouraged them to do things as quickly as possible, he said on Wednesday.
Boosters slump as new COVID wave picks up.
The winter season has brought a rise in COVID 19 hospitalisations, exacerbated by new Omicron subvariants.
Last week, Australia was second only to France in the number of COVID cases by population among the G 7 nations, according to the University of Oxford's Our World In Data project.
More than 95 per cent of people over 16 are fully vaccinated, but the number of people getting boosters has fallen since February.
Only 70.5 per cent of the eligible population has received three or more doses.
As of Monday, 59 per cent of people who were eligible had received a fourth dose, according to 2,413, 000 people.
The group said earlier this week that ATAGI continues to emphasize the importance of staying up to date with COVID 19 vaccinations by receiving the primary course and one or two booster doses based on eligibility.
The booster doses provide additional protection against severe disease, hospitalization and death as compared to the primary course. People who have recently been infected with the SARS-CoV-2 virus are advised to delay their booster shot until three months after their infection.
ATAGI had been waiting for the time to expand eligibility, according to ATAGI's vice-president, Chris Moy.
They have been pressured for a long time to go to a fourth shot for everyone, but they wanted to hold their shot, Dr Moy said.
Moy, who is a technical expert with ATAGI but not a voting member, said that opening a fourth booster for those older than 30 was unusual.
The evidence for that group is not super high, Dr Moy said.
There isn't a strong evidence for that except for a transient reduction in getting infection and transmission down the transient reduction.