All but one of Victoria's latest locally acquired COVID-19 cases were active in the community while potentially infectious, as the state identifies some 10,000 "primary close contacts".
Another 19 diagnoses were confirmed on Saturday, taking to 43 the state's total number of virus cases for the current outbreak as all of Victoria remains in a five-day lockdown.
Health Minister Martin Foley said the 18 people who were in the community before testing positive were moving about for an average of 1.7 days each and that was reassuring.
"That figure is a vindication of the going-hard-and-going-early strategy that the public health team has put to the government," he said.
The latest patients include at least two school students, and there are 14 cases linked to an "index case" - a man aged in his 60s - who attended last weekend's Geelong-Carlton AFL game at the MCG.
The number of exposure sites has reached 168, and includes pubs, clubs, restaurants, sporting venues, shopping centres, schools and gyms in metropolitan Melbourne, suburbs and multiple locations at Phillip Island, a two-hour drive south of Melbourne.
The AFL confirmed on Saturday that players from several clubs had visited exposure sites in recent days and have since travelled to Queensland.
Mr Foley said the potential threat to regional Victoria is ongoing.
"What we've seen over the last 24 to 48 hours is a list of exposure sites that now include significant parts of regional Victoria - Phillip Island, the Barwon region, Bacchus Marsh - and the primary and secondary contacts that have spread further than that."
Exposure sites and the latest information on COVID restrictions can be found at www.coronavirus.vic.gov.au while authorities declined to comment on the potential for the lockdown to last past Tuesday.
"There is enormous frustration for all of us about the uncertainty around this virus," Chief Health Officer Brett Sutton said.
"But you might as well read a horoscope to be able to predict how things might look three days from now. We're on a really good trajectory in terms of having every case linked, but we don't know what's around the corner.
"Those super-spreading events are becoming more common with the Delta variant. The transmission within any indoor setting is much higher than we've seen previously.
"We just need to brace ourselves for any possibility."
Victoria's COVID test numbers for Friday totalled 47,606 and 19,237 got vaccinated, authorities said.
"I don't think it's a state secret that we are a long way behind where we should be in the vaccination program," Mr Foley said.
"That is one of the factors that has helped shape the public health team's decision to go hard and go early (with a lockdown), because you cannot protect Victorians with what is, I think, 12 per cent of Victorians vaccinated."
He welcomed stricter measures announced by NSW on Saturday to do what it can to "keep the rest of Australia safe".
Queensland, Western Australia, South Australia and Tasmania have imposed barriers on travel from Victoria.
No overseas acquired infections have been recorded on Saturday.
Victorian exposure sites are listed here: https://www.coronavirus.vic.gov.au/exposure-sites