Victoria has reported 10 new cases of COVID-19 community transmission, as authorities turn away anyone trying to enter the state without an exemption.
The new cases recorded in the 24 hours to 8pm on Friday are all linked to the Black Rock restaurant cluster.
A further two cases in isolation have also been added to Victoria's tally, after they were detected earlier in NSW following travel to its south coast region in December.
Victoria now has 29 active cases in isolation across the state with about 220 close contacts also now in isolation, up from 50 on Friday.
Police are investigating after two people breached numerous public health orders after travelling from Victoria into NSW.
Health Minister Martin Foley said the pair fled from authorities at Melbourne Airport and drove to Goulburn in NSW. They each face a fine of at least $19,000.
"They came in from Canberra, they did not have the appropriate declaration material and they would have been heading straight into compulsory hotel quarantine," Mr Foley said.
"They disappeared in a vehicle and they were next heard of in Goulburn."
However, in a statement emailed to AAP the couple, named Terry and Debbie Elford, said they had no intention of defying authorities.
They were "really shocked" to discover media articles about themselves and contacted Goulburn police to sort out the matter, Mr Elford said. They got COVID tests and are self-isolating.
"We got caught up with the confusion when the rules about entering Victoria changed," he wrote.
"We were stopped by DHS officers who were not able to tell us whether or not we needed to quarantine, so after about an hour or so we walked away."
The Victorian outbreak has been directly linked to the NSW outbreak.
Mr Foley made no apologies for closing the border to NSW and said it was based on public health advice.
Victoria had been on a 60-day streak of no locally acquired coronavirus cases until three new infections emerged on Wednesday.
"Given all that we've sacrificed last year, I don't think Victorians would expect anything else from the government that wants to keep their safety and their wellbeing as its first priority," Mr Foley said.
AMA president Omar Khorshid said Victoria's situation was now potentially riskier than NSW.
"Victorians have borne the brunt of COVID-19 in Australia, and the prospect of returning to harsh lockdowns must be devastating," he said on Saturday.
The only people exempt from Victoria's closed border with NSW are border communities with permits and essential workers. Anyone else trying to cross will be turned back.
The southern state's decision to close the border at midnight on Friday led to traffic bottlenecks as people raced to beat the deadline.
COVID-19 testing sites saw long queues as travellers lined up for mandatory testing.
Those needing to cross the border now have to apply for an exemption, which the government says will take 24 to 48 hours to be completed.
Victorians can apply for exemptions via the coronavirus hotline on 1800 675 398.
Victorian exposure sites are now in: Black Rock, Brighton, Cape Schank, Cheltenham, Doveton, Forrest Hill, Fountain Gate Shopping Centre, Hallam, Glen Waverley, Lakes Entrance, Leongatha, Mentone, Mordialloc, Melbourne CBD, Moorabbin, Mount Waverley, Oakleigh, Southbank, and Wonthaggi.
Specific locations in those suburbs can be found on the DHHS website.
Western Australia, the Northern Territory, South Australia and Tasmania have all further hardened their borders as a result of the new Victorian cases.