The Therapeutic Goods Administration has ticked off on the vaccine for people aged 16 and over after it met strict standards around safety, quality and efficacy.
Two doses at least 21 days apart will be required, with aged care and disability residents and workers, frontline healthcare staff, as well as quarantine and border employees at the front of the queue.
While the program is now slated to start in late February instead of the middle of the month, the federal government has conceded shipping or production issues could delay it to early March.
The target of vaccinating four million people by late March has been pushed back to early April, with suppliers' global commitments affecting rollout speed.
"There will be swings and roundabouts on this process," Prime Minister Scott Morrison told reporters in Canberra on Monday.
About 80,000 shots are expected to be administered a week during the initial phase before ramping up to one million every seven days.
Mr Morrison said the vaccination rollout would not immediately lead to a relaxation of restrictions around international travel, social distancing or masks.
"It is not a silver bullet because there are still limitations to what these vaccines can do," he said.
Opposition Leader Anthony Albanese said the government should expand its vaccine portfolio to the world's best standard of five to six different types.
"The prime minister last year was saying that Australia was at the front of the queue - that's not true," he said.
Provisional approval means the Pfizer vaccine can be supplied for two years subject to strict conditions.
Health secretary Brendan Murphy said authorities had closely monitored concerns in Norway, where about 30 elderly frail people died after receiving the Pfizer jab.
"The TGA advice - and we have been concerned about this - for the very elderly and frail will need a very careful clinical decision," he said.
A World Health Organisation expert panel found no evidence the vaccine had contributed to the deaths.
Advice over vaccine safety for pregnant women is expected to be handed to the government before the jab starts to be administered.
It is not known whether vaccines stop transmission of coronavirus but data is expected to filter through in coming months.
"It stands to reason that these vaccines will also prevent, to some degree, transmission of the virus but we don't know how effective they are at doing that," Professor Murphy said.
He said Australia was not in a crisis mode necessitating 24-hour vaccination clinics that have been set up in other parts of the world.
TGA boss John Skerritt said the regulator would continue to monitor and review the safety of the vaccine.
"We now check the individual batches of vaccines that are destined for Australians while closely monitoring the safety and efficacy of the vaccine as it is rolled out," he said.
Regulatory review for the AstraZeneca and Novavax vaccines is ongoing.
Health Minister Greg Hunt said immunisation rates had risen during the pandemic, with more than 95 per cent of five-year-olds vaccinated for the first time.
Foreign Minister Marise Payne has started working with Australia's Pacific neighbours on preparations to vaccinate their populations.
Monday marks one year since the first coronavirus case was diagnosed in Australia, which has since had more than 28,700 cases and 909 deaths.
In stark contrast, there have been 25 million cases in the US alone and more than 400,000 deaths.