Australian Medical Association Victorian president Roderick McRae has urged the expert immunisation panel to approve third jabs.
"The vaccine status of those healthcare workers in particular who have had those two booster doses, their protection against COVID-19 is waning," he said on Wednesday.
"They should be looking after healthcare workers to ensure that they're as protected as they possibly can be as they have made the decision to open up the community."
But infectious disease expert Robert Booy said the focus should be on ensuring immunocompromised people were given another dose before Christmas.
"For the rest of the population who might be at higher risk, I can see a booster coming next year at the same time as a flu jab - March, April, May," he told the Nine Network.
"So no need to panic."
Professor Booy said immunity was started to wane but evidence from overseas - where vaccination rollouts started up to three months ahead of Australia - showed protection remained.
"If you're a standard, run of the mill person who is reasonably healthy you retain immunity - and that's after six to 12 months," he said.
He said immunising Pacific neighbours including Papua New Guinea was a more pressing priority than third jabs for health workers in Australia.
"I've been doing vaccine research for over 30 years. I always see a decline in antibody at six to 12 months. That's normal," Professor Booy said.
"What the immune system does is create a memory that you don't measure by way of antibodies but you measure in a different way."
He is concerned the virus could mutate in countries with low vaccination rates where deaths are soaring.
Australia is on the cusp of reaching a major national coronavirus vaccine coverage milestone.
The 70 per cent target for people aged 16 and over could be reached on Wednesday, as more travel and social restrictions begin to ease.
More than 85 per cent of over-16s have received a first jab, leaving about three million people yet to roll up their sleeves.