The nation's expert vaccine advisory group has recommended another 1.5 million Australians get a fourth COVID-19 vaccine.
Acting Health Minister Katy Gallagher confirmed ATAGI is expanding the eligibility for another booster to people with cancer, other complex health conditions and Australians living with a disability.
Currently, a fourth dose is available to anyone aged over 65, Aboriginal and Torres Strait Islanders over 50 and people who are severely immunocompromised.
Healthy people aged 16 to 64 — who do not fall into those categories — are not being advised to get a fourth dose at this stage.
Senator Gallagher said the fourth dose was essentially a winter booster.
"The idea behind expanding the criteria has been to ensure that people who are at the greatest risk of severe infection, the worst end of COVID-19, are protected," she said.
"The reason why it hasn't been expanded more across the general population is based on evidence. We have accepted the ATAGI advice in full.
"But the benefits of having a fourth dose for everyone … ATAGI's view at the moment is that's not required."
For people who have had COVID-19 and are now eligible, the government's advice is for them to wait three months before getting the fourth shot.
Senator Gallagher said there was no evidence of vaccine shortages and urged anyone who had not had a third dose to get it.