The Department of Health and Human Services says the five community COVID-19 cases detected on Thursday are primary close contacts of existing cases in the Mitcham and Mentone clusters.
Four of the new cases are in metropolitan Melbourne, and the other is in Leongatha.
DHHS also advises that contact tracing is under way in relation to two Victorians who tested positive to COVID-19 in NSW.
These two cases have not been included in Victoria's figures.
Victoria's COVID testing chief Jeroen Weimar has urged people throughout the state to remain vigilant, with more positive cases expected to emerge within the coming hours and days.
It comes as New South Wales records three new positive cases.
"We are concerned about the level of virus transmission in New South Wales," Mr Weimar said.
Links to the New South Wales outbreak remain the most likely source of the virus in Victoria, though Mr Weimar said the state was keeping an open mind.
Results from genomic testing are expected to become available in the coming days.
Victoria recorded no new locally acquired COVID-19 cases on Friday. However, five cases were confirmed on Thursday - three in the morning, two later in the day.
If you live in or have recently visited Lakes Entrance, watch for any coronavirus (COVID-19) symptoms. If you are experiencing fever, chills or sweats, a cough, sore throat, runny nose, loss of taste or smell or shortness of breath, get tested and stay home. (1/2) pic.twitter.com/frhdTKkI5S— VicGovDHHS (@VicGovDHHS) December 31, 2020
Mr Weimar said the lack of cases additional to the five reported on Thursday should not be cause for false confidence, nor false despair.
The number of primary close contacts to emerge from the Victorian outbreak has grown to 170, with many more identified as secondary contacts.
Mr Weimar said additional cases within those 170 close contacts would be a concern, but the state was still driving after the source of the infection.
He said the virus outbreak posed a risk to Victoria as a whole, not just to Melbourne or to bayside areas.
COVID-19 fragments were detected in wastewater at Lakes Entrance on December 29.
One of the state's positive cases was in Leongatha.
"If you've got symptoms go to your nearest testing station, no matter where you are," Mr Weimar said.
Everyone who is tested for coronavirus (COVID-19) helps us understand how the virus is spreading. If you have symptoms, however mild, please get tested.— VicGovDHHS (@VicGovDHHS) January 1, 2021
Use the list and map on this page to find your nearest testing location: https://t.co/ogHDjdmEZd#COVID19Vicpic.twitter.com/x2QSXRh3CE
He acknowledged hours-long waits for COVID-19 testing in parts of the state and urged people to persevere.
"You might be part of a new chain of transmission we don't have identified," Mr Weimar said.
"Bring a book, bring your iPad, and just wait in line to get tested."
He also acknowledged long waits for people seeking to re-enter Victoria before the state closes its border with New South Wales at 11:59pm.
"If you are in New South Wales and you want to be back in Victoria you need to leave now," Mr Weimar said.
"If you haven't left already, you need to prepare for a lengthy wait at the border."
Victorians returning to the state as of today need to get tested and self-isolate for 14 days.
A transit permit system is expected to be in place from tomorrow for people travelling back to Victoria from interstate via New South Wales.
Health minister Martin Foley thanked border communities for their patience in what had been a very difficult 12 months for them especially.
He reiterated restrictions that came into effect from 5pm on Thursday: that masks would be mandatory indoors.
Mr Foley said clients receiving beauty services could remove their masks if it was not practical to receive a service while wearing one, as in facials.
The same went for strenuous physical activity in gyms.
Victoria recorded no new locally acquired COVID-19 cases on Friday, according to the Department of Health and Human Services' daily update.
Friday's update included the five cases announced last Thursday, but no new cases were added to the tally on Friday morning, as 13,108 test results were received in the past 24 hours.
Victoria has recorded eight new coronavirus cases since last Wednesday, following a streak of 61 days without a locally acquired case and there are 18 active cases statewide.
Three people in the state's hotel quarantine system have been diagnosed with the virus, according to the update.
Victoria will close its border with NSW at 11.59pm on January 1, Acting Premier Jacinta Allan announced on New Years Eve.
"This is not an easy choice and certainly not one we wanted to be making and announcing on a day that is supposed to be about celebrating," Ms Allan said.
But she said Victoria had to remain vigilant and keep ahead of where the case numbers might be, particularly in light of the case numbers coming out of New South Wales.
The list of exposure sites compiled by DHHS can be found at www.dhhs.vic.gov.au/case-locations-and-outbreaks.
For more information, phone the COVID-19 hotline on 1800 675 398.
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