The nation's top vaccine advisory group is set to recommend a "winter" COVID-19 jab for some of the most vulnerable Australians on Friday.
Ahead of a feared surge in cases during the coming colder months, people over the age of 65 and those who are immunocompromised will be eligible for an extra dose.
Indigenous Australians aged 50 and over, as well as residents of aged and disability care facilities will also be eligible for an additional dose, with the first doses to be administered from the beginning of April.
For those eligible, it will be the fourth COVID vaccine dose they will have received since the vaccine rollout began.
In some cases it will be potentially the fifth COVID vaccine dose Australians with severe underlying medical conditions will have received.
Australia changed its definition of "fully vaccinated" against COVID to require three doses of a vaccine in February.
However, health authorities are eager to move away from "numbered" doses and make this "winter" jab more akin to receiving a seasonal flu vaccine.
They will also stress the importance of receiving a flu vaccine this year, as concerns mount that the country could be in for a bad season.
Cases of influenza have been very low since the start of the pandemic due to lockdowns and border closures.
The Australian Technical Advisory Group on Immunisation (ATAGI) is also expected to recommend people wait between four and six months between COVID vaccine doses or their last infection with the virus.
However, as with previous doses, there will be some variability in the interval to ensure people can get access to the vaccine.
In recent weeks, Australia has experienced increases in COVID-19 cases due to the arrival of Omicron subvariant BA.2.
Some concerns have been expressed about sick and elderly people whose protection might have waned over the past six months, due to their weaker immune response to vaccines.
Health Minister Greg Hunt has repeatedly said the country's vaccine advisors were studying waning immunity around the world and considering how the nation would manage COVID in the years to come.
Earlier this month, he indicated the next round of doses could be the beginning of an annual vaccine program.
"To be completely transparent about the latest thinking is they are potentially going to recommend a second booster, which would then be potentially the start of an annual program for people 65 and above," Mr Hunt said.
"[ATAGI] have been meeting now for many weeks to consider that question."
A federal election for May is expected to be called in early April, shortly after the additional doses begin to be administered.
The Health Minister is retiring at the election and is not recontesting his seat in Victoria.
