Those aged 16 to 39 will be eligible for Pfizer as Victorian authorities become increasingly confident that does will arrive from Wednesday.
Premier Daniel Andrews said it would essentially open the Pfizer program for nearly all Victorians and meant anyone aged 16 to 59 would be eligible to receive either Pfizer or AstraZeneca.
"Only one slight caveat on that - 16 and 17-year-olds are not eligible for AstraZeneca," he said.
Those aged over 60 will continue to get AstraZeneca.
Over the next four weeks there will be an additional 830,000 appointments for vaccinations at state run centres.
"This is a very significant expansion of the program," he said.
However, Mr Andrews said, there is not enough vaccination for everyone so asked people to be patient.
Additional staff will man booking systems tomorrow.
He urged everyone with existing vaccinations to keep their appointments.
Victoria has recorded 51 new coronavirus cases since Monday.
The new COVID-19 cases included 50 in the community and one in hotel quarantine.
Of the 50 local cases recorded, 40 are linked to current outbreaks and 10 are under investigation.
Just 11 of Victoria's 50 new local cases has been in quarantine during their infections period.
Victoria's active coronavirus case tally now sits at 522.
Tuesday also bought 48,424 test results to Victorians as well as 29,810 vaccinations being administered.