Victoria announced 10 new deaths from COVID-19 on Sunday, the largest single-day increase recorded in Australia since the pandemic began.
The casualties include three women and seven men, including a man in his forties. Seven of the fatalities are linked to aged care outbreaks.
Premier Daniel Andrews also announced 459 new cases on Sunday morning, up from 357 new cases on Saturday.
Eighty two of those are known contacts of people with COVID-19 and 377 remain under investigation.
The state death toll now sits at 71, with the national figure at 155.
There are 228 Victorians in hospital and 42 in intensive care.
Mr Andrews said the numbers were "far too high" but they were showing "relative stability".
"Whilst there is some relative, and I stress the term 'relative' stability, and I mean we are not seeing the doubles and doubling again - which is what the modelling told us we would have be dealing with - we've got to drive these numbers down," he said.
Victoria was approaching "the halfway mark", the premier said.
"We've been clear that it would get worse before it got better, but stability had to be achieved before we would start to see numbers fall."
He said it was unclear where the state would be in another three and a half weeks.
Stage 3 lockdowns have already been in place in Melbourne and the Mitchell Shire for 17 days, but have failed to bring down case numbers.
Victoria conducted 42,573 tests on Saturday, which the premier said was "by far and away the biggest testing result that we've seen on a single day".
Aged care has been severely hit by the state's second wave of coronavirus, with 560 active cases now linked to the sector, including 381 active cases among aged care workers, which was "a significant challenge", Mr Andrews said.
Healthcare, big distribution centres, meat works, cool stores and big warehouses are also driving Victoria's second wave, he said.
Mr Andrews urged Victorians with symptoms to get tested quickly to avoid more workplace clusters developing.
"The biggest message today is if you've got symptoms then please get tested and get tested quickly. And then stay at home until you get your result. And if you're positive then you have to stay at home for those 14 days."
He also urged people to take advantage of the $300 hardship payment that would support them while they awaited test results, if they were not entitled to income support from their employer.
The premier said 20 Australian Defence Force personnel would work alongside Ambulance Victoria paramedics in joint crews from Monday, a number that will grow to 150 staff over eight to 10 days and which is expected to free up 150 paramedics.
Thousands of retired health professionals and medical students were also putting up their hands to join the state's coronavirus response, Mr Andrews said.
But the premier reminded Victorians that health workers were "the last line of defence against this very, very infectious virus" and it was up to everyone to play their part by .
"If those directions are not followed, police are able to fine you. It is a $200 fine," he said, but added that if there was a genuine sense of error or confusion, police would use "good judgement".
Victoria Police issued 126 fines in the last 24 hours to those breaching coronavirus restrictions rules, with 20 issued to people failing to wear a face mask when leaving home for one of the four approved reasons.
NSW recorded 14 new cases of coronavirus on Sunday as the cluster linked to a Thai restaurant in Wetherill Park rose to 67.
Six of the state's new cases were linked to church and funeral services.
Federal deputy chief medical officer Nick Coatsworth said the situation in Victoria "has us all deeply concerned" but things were not spiralling out of control yet.
"What isn't happening of course is that those numbers are not doubling on a week-by-week basis," he told reporters in Canberra.
"That we have reached a relatively steady state for the moment of numbers between about 350 and 450 per day... reflects the effect of some of the initial restrictions that have been brought in."
Dr Coatsworth said 1,400 ADF personnel were currently in Victoria and additional defence force resources were available should they be needed.
"This is truly a national effort," he said.
He also addressed clusters in Victorian aged care homes and calls for residents in affected facilities to be removed, saying it was "difficult to apply blanket approaches across different facilities".
"The important thing to note here is that decision-making for individual aged care residents is a shared decision between themselves if they're able to make it, their families and of course healthcare practitioners," he said.
"It is important that people understand that there is no blanket approach, that these approaches need to be tailored, individualised and effective."
Residents in metropolitan Melbourne are subject to stay-at-home orders and can only leave home for essential work, study, exercise or care responsibilities. It is also mandatory to wear masks in public.
People in Australia must stay at least 1.5 metres away from others. Check your state’s restrictions on gathering limits.
If you are experiencing cold or flu symptoms, stay home and arrange a test by calling your doctor or contact the Coronavirus Health Information Hotline on 1800 020 080.
