The entire state is locked down and a police blitz is underway to enforce tough regulations and increased fines as authorities battle to contain the spread of the virulent Delta strain of the virus.
The four women who died in the 24 hours until 8pm on Tuesday were in their 50s, 60s, 70s and 80s, were not vaccinated and had underlying health conditions.
"September is the month when we're asking everybody to get ready," Premier Gladys Berejiklian said on Wednesday.
Victoria has recorded 120 new coronavirus cases, the first time the state has reached triple COVID-19 figures in a year.
The last time Victoria's case numbers exceeded 100 was on September 2 last year, when 110 cases were recorded.
Sixty-four of Wednesday's cases are linked to existing virus outbreaks, leaving 56 potential mystery cases.
Victoria has also recorded its first deaths in the current outbreak, after the health department revealed two women aged in their 40s and 60s died at home on Tuesday.
In the ACT, there have been 23 new cases recorded.