Australia has secured an additional 20 million doses of the Pfizer vaccine overnight, Prime Minister Scott Morrison has announced.
The additions bring the country's Pfizer vaccine total to 40 million doses in 2021.
It comes as the Australian Technical Advisory Group on Immunisation (ATAGI) issued an advisory for Australians under 50 not to receive the AstraZeneca vaccine.
LIVE UPDATES: Australia secures more doses of Pfizer vaccine
The extra doses are expected to be available in the fourth quarter of this year.
"We will obviously be doing everything we can to seek to move that forward where we can, but that is very welcome news, particularly in the light of the information that we received from ATAGI last night," Mr Morrison said.
Australia has entered into four separate agreements for the supply of COVID-19 vaccines.
Of these, 40 million are from Pfizer, 51 million from Novavax, 53.8 million from AstraZeneca and 25.5 million are from the COVAX facility. © NineAustralia has secured an additional 20 million doses of the Pfizer vaccine overnight, Prime Minister Scott Morrison has announced.
Australia's current population is currently around 25.8 million people.
The agreements total up to some 170 million COVID-19 vaccine doses.
Mr Morrison reiterated the advice provided to Australians last night in relation to the AstraZeneca vaccine was not a "ban".
"The recommendations that have been received from the Australian Technical Advisory Group on Immunisation (ATAGI) is not a ban on the AstraZeneca vaccine," he said.
"It is not a prohibition on the AstraZeneca vaccine, it recommends and notes that the risk of these side effects are remote.
"They are very rare. We are talking in the vicinity of five to six per million which is a rather rare event."
Health Minister Greg Hunt said phases 1A, 1B and even 2A will be "largely unchanged" by updated advice surrounding the AstraZeneca vaccine for people aged under 50.
"For those who may be immunocompromised or front-line workers who are under 50, right now we are working with the states and territories and the medical authorities to revise that part of the program so they have access to Pfizer," Mr Hunt said.
"That will take time - we recognise that as those Pfizer doses become available, but we are working on that front."