"What we have at the moment are numbers that are too high of community transmission and that is a concern to us", he told reporters.
Premier Daniel Andrews confirmed that stage four restrictions will be introduced on Sunday as Victoria recorded 671 new cases and seven deaths as a result of COVID-19.
"This will be in addition to the state of emergency that's operated throughout", Andrews said.
Andrews said his government was deeply anxious that 49 "mystery cases" identified on Saturday could indicate the virus was spreading widely through the Melbourne community and confirmed he was in discussions with Australian Prime Minister Scott Morrison about tougher restrictions.
Victoria Premier Daniel Andrews hasn't explained exactly what "stage four" will mean yet. "And the children, the students of parents who are working, they'll be able to go to school and be supervised - but it will really only be those that are absolutely necessary to do so".More news: Arsenal lead the race to sign FC Barcelona midfielder
'We can suspend various acts of the parliament and make sure that we get the job done and there's no question about the enforceability and the way in which new rules will operate'.
The state's chief health officer, Brett Sutton, said a New Zealand-style lockdown was being explored - restrictions which saw all businesses closed except for essential services.
"If you take further steps you've got to make sure you've put it through properly, that the rules can function and that any changes to the rules will actually deliver the desired outcome".
'We need to do more. That is what these decisions are about'.
Under the "stage four" restrictions, Melbourne residents will only be allowed to exercise for an hour a day and can't travel more than 5km from home for the goal of shopping.More news: Rihanna on her next album: 'It's going to be worth it'
From Sunday night, a curfew from 8pm to 5am will be put in place across Metropolitan Melbourne and exercise will be limited to one hour daily within five km of home. Under the new restrictions, they would have to stay within 5 kilometres (3 miles) of their homes, with only one person from each household allowed to go to grocery shopping.
Regional Victoria will move to stage three restrictions from Thursday.
The premier flagged further announcements would be made about workplaces on Monday, including the closure of certain industries.
Active cases in the state's aged care system on Saturday surged beyond 1000 - with outbreaks in 100 different homes - for the first time since the pandemic began.
Victoria is expected to report 650 new coronavirus cases later today, as the state appears headed for an unparalleled stage 4 lockdown.More news: SpaceX capsule with astronauts returns to Earth