Four of those cases had already been announced yesterday.

Premier Daniel Andrews is today expected to announce some sort of timeframe in which Victoria could be released from its fifth lockdown.

The restrictions were originally scheduled to ease at midnight on Tuesday, but will be extended.

In total yesterday, there were 49,454 tests returned and 17,083 vaccines delivered.

As of yesterday, there were still no cases in Ballarat and no new exposure sites near the city.

See the full exposure site map here.

"It would be perhaps a few days of sunshine and then a very high chance we'd be back in lockdown again, that's what I'm trying to avoid, trying to make sure we do this properly and bring these cases to an end," Mr Andrews said when announcing the extension of the lockdown on Monday.

"This lockdown will be on only as long as it needs to be, not a moment longer but we don't want a situation where we fail to extinguish this, fail to end these chains of transmission only to open again and close again shortly thereafter."

Almost a third of Victoria's locally-acquired coronavirus cases can be traced back to a sports fan who attended an AFL match, a Euro 2020 viewing party and the rugby while unknowingly infectious.

The man, aged in his 30s, contracted the virus at the Geelong-Carlton game at the MCG on July 10.

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He was seated in the MCC Members' Reserve near a man in his 60s who lives at the Ariele Apartments in Maribyrnong, which had been visited by a COVID-infected removalist crew from NSW a day earlier.

About 30 hours later the younger man was at a viewing party at the Crafty Squire in Melbourne's CBD, watching Italy beat England in a penalty shootout to win the Euro 2020 championship.

At about 8am on July 12, he left the event and headed to Trinity Grammar in Kew, where he works as a teacher.

The next day, he had dinner at Ms Frankie in Cremorne with 12 friends before heading to the Australia-France rugby union test match at AAMI Park.

The man had no idea he was infected with the Delta variant and was not presenting with symptoms at the time.

Twelve staff and patrons of Ms Frankie, six students and staff at Trinity Grammar, three people at AAMI Park and one person at the Crafty Squire have since tested positive for COVID-19, sparking their own chains of transmission.

Victoria's Chief Health Officer Brett Sutton said it proved the speed and ease with which the Delta variant spreads.

"It is absolutely an example of how quickly this variant is moving and the short time we're seeing between exposure and then being infectious," he told reporters on Monday.

"Last year we would not have seen any circumstances where someone who had been exposed was transmitting to someone else a day and a half later."

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