Victoria's health department has written to federal authorities seeking clarification on expanding the vaccine rollout to Australians under 40.
Prime Minister Scott Morrison said all Australians, no matter their age, will soon be able to get their AstraZeneca jab at GP clinics as part of an indemnity scheme.
It will protect GPs from any litigation when administering AstraZeneca to willing Australians, given Pfizer remains the vaccine of choice for under 60s due to extremely rare instances of blood clots.
In Victoria, most people under 40 have not been eligible for any vaccine whether it be AstraZeneca or Pfizer
However, Health Minister Martin Foley said the expansion of the rollout to anyone under 40 had not been agreed to during Monday night's national cabinet meeting.
"This morning the Department of Health has reached out to the Commonwealth to request advice about the eligibility requirements formally changing," he told reporters on Tuesday.
There are reports some GPs have knocked back requests from Victorians under 40 to get the AstraZeneca shot as they await official advice on the change.
Mr Foley urged people aged 18 to 39 to remain patient in the meantime.
"If there's a degree of confusion out there with the GPs as we seek to roll this out, it's not by anyone in the GPs or the state clinics planning," he said.
"As soon as we get all the information and clarification from the Commonwealth, we will implement the system as quickly and as smoothly as we possibly can."
Earlier, Premier Daniel Andrews welcomed the rollout tweak but noted Victorians aged 18 to 39 still won't be able to walk up for their long-awaited shot at mass vaccination hubs across the state.
"It's part of the Commonwealth exclusive side of this," he told ABC radio on Tuesday.
He will consider broadening the order to Victorian-run centres, if supply can be boosted.
"It's not about 'have we got enough nurses, have got enough physical space?'. They're not limiting factors," Mr Andrews said.
"The only limiting factor at the moment is, do we have enough supply to get into as many arms as we can as fast as we can?"
More than 18,000 Victorians received a vaccine dose at state-run hubs in the 24 hours to Tuesday morning.
It comes as Victoria recorded its third consecutive day without a local COVID-19 case and continues to ramp up its road border regime.
The Health Department confirmed no new locally acquired infections on Tuesday, following more than 20,000 tests.
Two returned travellers in hotel quarantine tested positive, with active cases in the state falling to 44.
Meanwhile, police patrolling the Victorian-NSW border are cracking down on travellers trying to sneak south of the Murray River.
Some 260 officers have descended on Victoria's northern border, checking vehicles with automatic number plate recognition technology.
While local border residents can still cross freely into Victoria, Sydney and surrounding areas remain red zones and other parts of regional NSW and the ACT have been classified orange zones.
Since the operation started late on Friday, police have turned away 53 people - most for coming from a red zone - with just a warning when they didn't have a valid permit.
But Chief Commissioner Shane Patton said the discretionary window was rapidly closing, with ineligible travellers now set to face a $4957 on-the-spot fine.
"From here on in, you're going to see much stricter enforcement," he said on Monday.
This includes helicopters scanning vehicle number plates on the Hume Highway from Monday and fixed-wing aircraft patrolling the length of the border from mid-week.
