Victoria has recorded one new locally acquired COVID-19 case, that of a known primary close contact who has been quarantining throughout their infectious period.
Officials also reported three new overseas cases on Saturday morning, all in hotel quarantine.
Travellers from NSW COVID-19 hotspots wanting to cross into Victoria have been sent a stark warning, as a community outbreak in Sydney balloons to 82 cases.
Health Minister Martin Foley emphasised the beefed-up police presence on the Victoria-NSW road border on Saturday.
"The message is simple. Don't come from a NSW red zone to Victoria. To Victorians, do not visit those red zones in NSW," he told reporters.
Police have stationed extra officers at the interstate border and are conducting spot checks and using licence plate recognition technology.
Travellers run the risk of being turned around at the border or even facing a fine of up to $5,000.
At Melbourne airport, 19 flights from Sydney arrived on Friday and more than 1,300 travellers have gone into quarantine. Fifteen travellers were sent directly back to Sydney after being in a designated red zone, Mr Foley said.
The new Victorian case recorded on Saturday is a household contact of a confirmed case in a cluster at Southbank, which is part of the outbreak that sent Melbourne into its recent fourth lockdown.
Their infection has not prompted any new exposure sites or contacts.
On Friday, Mr Foley said Victorians could rest assured that two local cases recorded on the previous day would not lead to rampant further infections.
He said he was confident the few additional infections would not impact on the school holidays.
"We have in place a system for the next two weeks that we are confident can withstand any of the challenges that the public health team have identified so far," he told reporters.
Chief Health Officer Brett Sutton confirmed the two infections had been linked genomically to the Sydney outbreak and its Delta virus variant.
Henry Li, who has owned Sandringham Dry Cleaners in Melbourne's southeast for 19 years, and his colleague are in hotel quarantine after testing positive.
Mr Li's colleague - an Oakleigh man in his 60s - tested positive on Thursday after returning from Sydney at the weekend, then Mr Li also tested positive.
"It's terrible - we did everything carefully, we still got it. I don't know what happened," Mr Li told 3AW.
He said they wore masks at work, used hand sanitiser and made sure customers checked in with a QR code.
Mr Li is in good health but says his employee is struggling with "quite serious symptoms".
The Oakleigh man is believed to have contracted the virus during a party at his daughter's house in West Hoxton in Sydney - the suburb was a "green zone" at the time.
That Saturday night party has since been declared a super-spreader event.
The man returned to Melbourne on Jetstar flight JQ523, which left Sydney at 5.30pm on Sunday.
The flight has been listed as a tier-one exposure site, meaning 126 passengers on board plus flight crew must get tested and isolate for 14 days.
The man took a bus from the airport to Broadmeadows and boarded a train from Broadmeadows to Flinders Street, then Flinders Street to Oakleigh to get home.
The bus and two trains are tier-two sites, meaning any other commuters will need to isolate until they get a negative test result.
The three train stations and a number of shops including a Woolworths in Burwood East and a shopping centre, fruit shop and Asian grocery in Forest Hill are also exposure sites.
The Sandringham dry-cleaning business has been listed as a tier-one site and about 100 customers are being traced.
Mr Foley said 13,000 people who had travelled from Greater Sydney since 11 June had been contacted and asked to get tested because of the outbreak in the NSW capital.
The health department confirmed 21,991 tests were processed in the 24 hours to Friday morning, while 18,019 Victorians received a vaccine dose at one of the state-run hubs.
