Australians will start to be vaccinated against coronavirus in February, following new advice provided to the federal government.
Prime Minister Scott Morrison said the Therapeutic Goods Administration was expected to receive all of the data it needed from vaccine developer Pfizer in mid-January, with approval due by the end of January.
"It is moving considerably faster than normal vaccine approval processes but without skipping a step, without cutting a corner," Mr Morrison told reporters in Canberra.
The approval process regarding another vaccine, by AstraZeneca, is due to be completed in February.
Mr Morrison said Pfizer's global protocols required about two weeks for delivery post-approval.
He anticipated there would be some logistical issues as the vaccine had to be stored at minus-70 degrees Celcius.
After delivery of the vaccines there would be up to a week required for batch testing of the vaccine doses.
The Pfizer vaccine would require a second dose within a couple of weeks to a month.
The first group to be vaccinated through a network of up to 50 "hub" sites would be quarantine and border workers, frontline health officials, aged care and disability workers and aged care residents.
Mr Morrison said it was hoped to achieve around 80,000 vaccinations a week and see that build up over a period of four to six weeks, with four million people vaccinated by the end of March.
Health Minister Greg Hunt, who earlier this week spoke about a March initial launch, said new advice from the TGA and shipping firms had led to the revised timetable.
Once the AstraZeneca vaccine was approved and available it would be rolled out through 1000 sites to older Australians, indigenous people, high-risk workers and people with particular clinical conditions.
Then the program would be made available via GP clinics and pharmacies to the broader population, with children last on the list as they are at the lowest risk of getting the virus and transmitting it.
Health Department secretary Brendan Murphy said officials had been working on plans for the rollout 24 hours a day to ensure it could be delivered safely and effectively.
"We want to make sure everything is set to go, so when we start vaccinating we have a well-oiled machine," Professor Murphy said.
It will be made available free and won't be mandatory.
Mr Morrison said he would receive the vaccine at Canberra Hospital in a televised event in a bid to ensure public confidence.