Victoria has recorded 24 new local cases of COVID-19, as a skate park and residential towers are among two venues of concern in Melbourne.
The figures come as health authorities are renewing their warning about the dangers of coronavirus in children.
Of today's new infections, 20 are linked to known outbreaks and 18 have been in isolation for the entirety of their infectious period.
A total of 39,382 tests were received in the past 24 hours.
Meanwhile this morning playgrounds and skate parks across Greater Melbourne are now roped off to prevent the spread of the highly contagious Delta variant.
There are currently 50 children under the age of 10 now fighting the virus in the state.
GP and former president of the AMA Dr Tony Bartone said the closure of children's play areas was "a contentious point".
"Children in this current outbreak are being overrepresented in the numbers, you might say, but that shouldn't be surprising given that they are not able to be vaccinated and the elder parts of the population are approaching higher levels of vaccination," Dr Bartone told Today.
He said authorities had "every right" to investigate the potential exposure at outdoor playgrounds "while we are at this really precarious state".
"Clearly, once we have got that information, if it is not proven to be the case, we need to balance the mental health impacts and the wellbeing impacts by not allowing children into that playground area and providing their daily routine or their daily exposure to exercise and enjoyment."
A number of the state's new infections are from suspected cases of outdoor transmission, prompting the crackdown of children's play areas including a skate park in Jacana.
In another case, two children walking home together may have caught the virus off each other with that infection now under investigation.
Residents of an apartment tower on Lyon Street in Carlton are being told to get tested immediately after the block was listed as a tier two site overnight.
A childcare centre and a number of shops have also been added to the growing list of exposure sites.
Five mystery cases in St Kilda and surrounding suburbs have authorities on high alert.
Dr Bartone said everyone needed to be on high alert when mystery cases were at play.
"What it does really say is that until we can link all the cases, and be clear on the source of transmission, we are really have to remain vigilant and be very, very concerned and get tested."
He also suspects the lockdown will be extended again. Thursday will mark 200 days of lockdown across the state.
"Until testing numbers increase significantly above 30,000 a day, inside of all of those mystery cases, it doesn't look promising at this stage."
Yesterday Victoria recorded 24 new cases.
A full list of the new exposure sites can be found here.