Victorian Premier Daniel Andrews said although “a doughnut day is always terrific,” a day where every positive case is isolating while infectious is the goal.

“You could have four, five, or 20 cases but if they were all tucked away from other people, isolating and can’t have given it to anyone else, that’s as good as a zero-day,” he said.

“Zero is always the aim, but it’s not zero cases. It’s zero cases that were out and about potentially infecting others.

“The mysteries are a concern to us but we’re all working to try and solve the puzzle to find out where these cases were.”

COVID-19 response commander Jeroen Weimar said of most concerning was how many exposure sites are now active.

The list grew to over 100 during the course of the press conference.

“We’re seeing a very significant number of cases coming through and it’s a number of significant transmission sites that are now are now active,” he said.

“The other biggest priority for us is to establish how many more cases we may have had upstream so that we can establish all those different chains of transmission.”