Less than three per cent of Australians over 16 have been fully vaccinated against coronavirus but health chiefs are tipping numbers will soar in coming weeks.
The sluggish national rollout of jabs continues to spark concern with Melbourne in the grips of another lockdown-inducing outbreak.
While the immunisation program is ramping up, just 613,000 people, or about 2.9 per cent of the nation's adults, have received both doses.
Chief Nursing Officer Alison McMillan is confident that figure will grow significantly with many people nearing the 12-week gap between AstraZeneca shots.
Case numbers have remained relatively low in Victoria but an emergence of the Delta and Kappa strains prevalent in India are causing authorities concern.
Professor McMillan declared vaccination would be the only way to counter emerging variants.
"There are multiple strains and we will continue to see COVID adapt and mutate - that's what these viruses do," she told Sky News on Tuesday.
"We're likely to see other strains emerging. The sooner we can get the world vaccinated, the less likely it is that it can mutate.
"It mutates and finds it easier to do when there's a significant population infected at any one time."
More than five million doses have been administered nationwide including more than one million over the past 10 days.
With the federal government under sustained pressure over the rollout's pace, more categories of Australians have been added to the eligibility list.
National Disability Insurance Scheme participants aged over 16 have been included in the program, which was opened to all Aboriginal and Torres Strait Islander people last week.
From Tuesday, all Australians over 40 will be eligible for a jab while the Northern Territory is set to become the first jurisdiction to offer all of its citizens a chance to be immunised.
Prime Minister Scott Morrison noted there were thousands of cases each day in major developed countries where vaccine rates have been high.
Mr Morrison said Australia was in a rare position of having a stronger economy than before the pandemic hit.
"That will continue so long as we get the balance of risk right in our judgements when it comes to any lockdowns," he told reporters in Sydney.
"It must be proportionate. It must be targeted. It must be temporary."
He stopped short of criticising the Victorian government over the lockdown which is due to ease on Friday but reiterated restrictions should ease as soon as possible.
The Therapeutic Goods Administration has given the green light for businesses to offer rewards for people who have been vaccinated.
The rewards could include store vouchers, discounts or frequent flyer points, but cannot include alcohol, tobacco or medicines other than listed medicines.
Any offer of a reward cannot be restricted to only those who have a vaccination after the reward has been announced.
They must be made available to those who have already received their first or second doses.
The TGA is also weighing up extending Pfizer jabs to 12 to 16-year-olds.
Australian Associated Press