Australia has struck a deal for 10 million more doses of the Pfizer coronavirus vaccine, doubling the country's supply.
Clinical trials have found the vaccine is 95 per cent effective after two shots, with the first Australians on track to receive the drug later this month.
Elderly and vulnerable people will be the first to receive the jab along with frontline health, border and quarantine workers.
Prime Minister Scott Morrison announced the increased supply on Thursday, saying the country was ahead of many others on vaccines.
"It is the big agenda item for us, obviously, because it provides the pathway to so many of the other things we wish to achieve this year," he told reporters in Canberra.
Pfizer's first 80,000 doses remain on track to be delivered this month but shipment sizes beyond that are not certain, with the company to update the government in mid-February.
Health Minister Greg Hunt is confident a diplomatic skirmish over vaccines between the European Union and the UK has calmed, shoring up the flow of supplies.
He said Pfizer had guaranteed all 20 million doses - enough to vaccinate 10 million people - would be delivered to Australia this year.
However, Mr Morrison acknowledged there were some issues beyond the government's control.
"Of course, there are some uncertainties that are obviously there regarding supplies, particularly from overseas," he said.
Everyone in Australia will be offered vaccination including temporary visa holders and people in detention centres.
Australia has also secured almost 54 million doses of the AstraZeneca vaccine, the vast majority to be manufactured in Melbourne, and more than 51 million from Novavax.
Studies show AstraZeneca is less effective than Pfizer but health experts insists it still prevents coronavirus death and serious illness in all recipients.
Health secretary Brendan Murphy said all three vaccines had been proven to be highly effective at preventing severe coronavirus.
"That is a position that we wouldn't have dreamt of a year ago, six months ago," he said.
The Pfizer vaccine received approval from the Therapeutic Goods Administration last week, while AstraZeneca is on target to get the green light before being rolled out in early March.
Novavax is less advanced in the approval process.
Mr Morrison said the nation now had access to 150 million doses of vaccines across the portfolio of drugs.
He will receive the Pfizer vaccine in the early stages of the rollout in a bid to boost public confidence in the rollout.
Victoria remains on high coronavirus alert after a worker at a quarantine hotel for Australian Open players and staff tested positive.
Authorities are hopeful the early signs are showing there won't be a major outbreak but compulsory masks and gathering limits have been reinstated.
Western Australia's five-day lockdown is on track to end on Friday after a fourth-straight day without a new infection.