There were 30 new coronavirus cases on the first day of a 14-day lockdown affecting the most populous areas of the state including Greater Sydney.
Acting Victorian Premier James Merlino said the government would not hesitate to harden the border if that was the health advice.
Victoria Police has more than 250 officers now dedicated to Operation Sentinel border patrols.
They will be performing roving patrols, pop-up checkpoints, spot checks and using automatic number plate recognition technology.
This will support the current vehicle patrols around the NSW border working to identify car registration details and vehicles who may have travelled from NSW, including those who may have been in a ‘red zone’.
All areas in Greater Sydney including Central Coast, Shellharbour, Blue Mountains and Wollongong were declared a red zone at 1 am on June 25.
Anyone who has been to a high-risk exposure site in NSW must quarantine for 14 days and cannot enter Victoria.
Victorian residents who have been in a red zone other than for transit, can obtain a red zone permit to enter Victoria but you will be required to quarantine at home for 14 days and get tested.
Victoria Police will be enforcing the border restrictions and an on-the-spot fine of nearly $5000 apply.