National cabinet could announce a changed definition of "fully vaccinated" to three doses, as early as Thursday, according to Victorian Premier Daniel Andrews.
Mr Andrews said a third dose is just as important as a first and second dose.
"This is not a two-dose thing (or) two doses and a bonus - it is absolutely critical and essential," he told reporters ahead of national cabinet meeting on Thursday.
"International evidence, our own experience, the views of experts and hopefully confirmation of both ATAGI and national cabinet today will mean everyone knows and understands this is a three-dose project."
When asked directly whether there could be national cabinet agreement of updating the definition to three doses, Mr Andrews said he "certainly hopes so".
"Hopefully we get that confirmation today," he said.
Mr Andrews said people want their three-dose status to mean something but any changes wouldn't come into effect immediately.
However, Tasmanian Premier Peter Gutewin said the ATAGI advice had not been provided to leaders ahead of national cabinet.
Opposition Leader Anthony Albanese said it was critical the health advice from experts be followed.
"What is clear is that the booster shot makes a major difference in terms of the Omicron variant in particular," he told reporters on the NSW south coast.
"Over a period of time it will be considered you would have to have had a booster in order to be fully vaccinated .... we know the protection (of a second dose) reduces over a period of time."
National cabinet will also discuss the state of the health system, following one of the deadliest days of the pandemic with 87 fatalities on Wednesday.
Australia's retail sector is urging national cabinet for isolation exemptions to be extended to staff in the industry, as the prime minister meets with state and territory leaders.
Isolation rules for workers in a number of essential sectors were expanded earlier this month, and now there is a growing push for retail staff to be added to the list.
The exemptions would allow workers to go back to their jobs after being at a COVID-exposure site, provided they test negative to the virus on a rapid antigen test.
Chief executive of the Australian Retail Association Paul Zahra said it was time to live with COVID.
"If you can expand isolation exemptions for certain groups, it makes sense to expand it further to other categories of retail," he told ABC Radio.
The Australian Chamber of Commerce and Industry has stepped up its push for international tourists to return to the country.
The chamber's chief executive Andrew McKellar said such a move would be a way to boost the post-pandemic economy.
"We are urging government to get ahead of the curve, start talking to the industry about how quickly it can happen," he told ABC TV.
"We do think in the weeks ahead, as the pressure comes off the health system, then the rationale for keeping these international border restrictions in place can be revisited."
Opposition home affairs spokeswoman Kristina Keneally said more planning was needed to allow the international travel sector to recover following years of uncertainty.
"We need to look at sensible solutions and it would be helpful if we actually had a national government that was leading," she said.
It comes as Victoria recorded 13,755 new cases on Thursday with 15 fatalities from the virus.
In NSW, there were 29 virus-related deaths and 117,316 cases, with nearly 10,000 of those coming from PCR tests.
Queensland recorded another 15 COVID-19 related deaths and 11,600 new cases.
