Premier Daniel Andrews said Australian Defence Force personnel and public health officials did more than 500 visits to positive cases on Thursday, but one in four were not home.

“There were more than 130 unsuccessful visits,” he said.

“There’ll be a multitude of reasons for that, but what I can confirm for you is that more than 100 cases have been referred to Victoria Police.”

The premier said there was no excuse for people who have tested positive not to be isolating.

“It is simply unacceptable for you to have this virus and not be at home,” he said.

“There may be a handful who are out, getting some fresh air – that does not explain these numbers, these numbers go well and truly beyond anything like that. And all that will do is spread the virus.”

The latest fatalities were two men in their 50s, two men aged in their 70s, three men in their 80s and one woman in her 70s. Four of the eight are linked to aged care homes.

The deaths take the state toll to 112 and the national figure to 197.

Chief Health Officer Professor Brett Sutton said workplace transmission was a significant factor in driving large case numbers, particularly those with a younger workforce who may not exhibit symptoms.

“Clearly there’s a concern that there’s a broader cross section of workplaces transmission between workplaces and home and back again. That’s contributing to the significant numbers,” he said.

Prof Sutton said while Victoria’s surge was disappointing, the lockdown was having an effect.

“It’s dispiriting to see big numbers and we all rise and fall with the numbers every day,” he said.

“The stage three restrictions had a really significant impact and people should be gratified by the fact that that’s the case.”

But the premier said the current lockdown could not be lifted with case numbers so high, and flagged further restrictions were possible.

“Public health experts from the Victorian team, together working with colleagues at a national level, will spend the next day looking through in fine detail, looking for trends to have a really clear sense of exactly what is presenting and exactly what the nature of our challenge is,” he said.

“We cannot open up with these numbers, we cannot open up with significantly less than these numbers.”

Mr Andrews also said the $300 isolation payment had been made to 4200 workers awaiting test results and who face hardship for not going to work, at a cost of $1.26 million.

So far 12,600 businesses have received a $5000 grant, worth around $63 million in total.