Prime Minister Scott Morrison said regulators were now expected to approve the Pfizer/BioNTech vaccine by the end of January.
He announced the plans on Thursday as the cities of Sydney and Melbourne battled to control new clusters.
By March, four million Australians could be vaccinated, he said.
"We are now in a position where believe we will be able to commence vaccinations in mid-to-late February," Mr Morrison said.
Following regulatory approval, the first of the country's order of 10 million Pfizer vaccine doses should be issued in a matter of weeks.