Mr Andrews confirmed nine of Victoria's new local cases announced earlier were in isolation during their infectious period.
"Of those 13 cases, nine of those 13 were isolating 100 per cent of their infectious period. So they were tucked away, away from others, no risk to public health. That is very, very promising," he said.
"With hope that continues and develops as a trend and with see more and more days where the majority and then hopefully 100 per cent of any new cases have been isolating for the entirety of their infectious period.
"That is really how we will know that we have brought this under control."
Mr Andrews is expected to make an announcement on payments to businesses on Wednesday.
Victoria's lockdown will be extended into early next week after the state recorded more new local coronavirus cases.
Premier Daniel Andrews confirmed the lockdown would continue to midnight Tuesday, July 27.
"We wish we could bring this in earlier, but we can't run the risk that there are cases out there that we don't know about," he said.
"There are changes of transmission that are not yet contained that we don't know about and if we would open up we would see how quickly this runs, we see how challenging this can become in a very short space of time.
"We need to avoid what is going on in Sydney at the moment. We are determined to do that."
There will be no changes to general public health rules, apart from amendments in relevance to school children with special needs.
This means the five essential reasons to leave home will remain in place state-wide, including shopping for essentials, exercise, medical reasons or care-giving, authorised work or education and to get vaccinated.
Victorians must also stay within five kilometres of their homes.
Masks remain mandatory indoors and outdoors.
From Wednesday, July 21 more students with disability will be able to return to on-site learning.
Where a parent or carer indicates that a student with a disability cannot learn from home due to vulnerability or family stress, the school must provide on-site learning for that student.
This change will apply to students enrolled in specialist schools and students with a disability enrolled in mainstream schools.
Mr Andrews announced any travel to Victoria using red zone permitswould be temporarily paused.
Changes to permits mean there will be no further red-zone travel for the next two weeks, though there will be exemptions on compassionate grounds.
It comes as South Australian premier Steven Marshall announced the state would go into a one-week lockdown from 6pm Tuesday.
Health authorities confirmed South Australia's outbreak was the Delta strain, prompting the state to tighten restrictions.
The Victorian Health Department confirmed it recorded 13 new local infections in the 24 hours to Tuesday, four of which were previously announced by authorities.
Twelve of the cases are linked to the current outbreaks of the Delta variant in the state, which originated in NSW, while one case remains under investigation.
The state also recorded two cases in hotel quarantine, bringing the total number of infections to 96.
More to come
- with AAP
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