But the government's case for keeping regional areas also in lockdown was strengthened with positive detections at Benalla and Healesville in recent days.

Mr Andrews also pointed to Armidale in northern NSW going into a seven-day lockdown on Saturday as evidence of how quickly the Delta variant could spread.

"In regional Victoria whether it is Wangaratta, where I grew up, or any other part of regional Victoria, there are mystery cases," he said.

"We've got wastewater (detects) in Benalla and Healesville, separate to the Wang' issue.

"We apologise. We try and get the best information out as quickly as we can. Nothing is perfect and no one has ever pretended that it is.

"Wastewater is not the only reason why people are locked down across the state.

"The most important reason is we have mystery cases, at least two, and we don't know where they've come from.

"On that basis everyone is at risk."

IN OTHER NEWS

On the day the latest lockdown was announced, Mr Andrews said a sewerage test in Wangaratta had "pinged" positive initially, then went negative before being positive again.

But less than 24 hours later Wangaratta mayor Dean Rees disputed the chain of events based on advice he had received from Northeast Health Wangaratta.

Victoriab COVID-19 commander Jeroen Weimar then contacted council chief executive Brendan McGrath to confirm there had been successive negatives following the initial positive detection on July 30

Ovens Valley MP Tim McCurdy led the charge for Mr Andrews to own up to his mistake.

"I'm speechless. The Premier has a history of not wanting to apologise for his failures," he said.

"But in this instance I am pleased he has and we can all move forward and hopefully have the regions removed lockdown."

Benalla's latest positive wastewater detection was recorded on Thursday with the most recent being in May and back-to-back positives were also recorded in late April.

There were 196 COVID tests carried out in Wangaratta on Friday.

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