SYDNEY -- Australia on Monday began its mass COVID-19 vaccine program with frontline healthcare staff and senior citizens getting the first doses as the country looked set to report no local cases for the third straight day.

A group of 20 that included Prime Minister Scott Morrison on Sunday received the first shots of the vaccine while the broader rollout started Monday morning with authorities expected to administer more than 60,000 doses by the end of the week.

"Today is a real milestone in our collective response to tackle COVID-19 and bring things as rapidly under control as we can," Acting Chief Medical Officer Michael Kidd told the Australian Broadcasting Corp television.

The vaccine, jointly developed by Pfizer Inc and Germany's BioNTech, will be rolled out in the initial weeks while AstraZeneca's first batch is expected to reach the country in the next two weeks.

The exercise, called a "game changer" by Morrison, is being billed as one of the most complex logistical operations in the country's history as the Pfizer vaccines need to be stored below minus-70 Celsius.

The vast majority of Australia's 25 million population will be injected with the AstraZeneca vaccine, which will be produced locally by CSL Ltd by the middle of March. Authorities plan to inoculate four million by March and expect to finish vaccinations by the end of October.

Victoria, the country's second-most populous state, on Monday reported no new cases for the third day in a row, suggesting a fresh outbreak in state capital Melbourne has been contained. Other states and territories have effectively eliminated the virus.

With just under 29,000 cases and 909 deaths from the virus, Australia largely escaped the high number of infections and deaths compared with other developed countries, helped by border closures and speedy tracking systems.