Victorians have been told they will be informed if they have come into contact with any of the four workers at a Melbourne hospital who have tested positive for the coronavirus.
That commitment comes as the state government launches a new text messaging system to check on hundreds of close contacts of confirmed cases who are in isolation.
Victoria's coronavirus tally rose to 466 on Wednesday after 55 cases were confirmed overnight.
Four of the total cases are workers at Werribee Mercy Hospital in Melbourne's outer west.
The hospital has confirmed one emergency department worker tested positive to COVID-19 on Sunday.
Fellow staff members considered at risk of infection were isolated and tested, with three confirmed as also having the virus.
The emergency department remains open after being "systematically sanitised", a Mercy Health spokeswoman says.
Victorian Chief Health Officer Brett Sutton has stressed anyone who may have come into contact with the healthcare workers will be informed and asked to enter quarantine, as with all confirmed cases.
"No one is kept in the dark about a potential exposure they might have had," he said on Wednesday.
Health Minister Jenny Mikakos said the Victorian government is "significantly expanding" the team tracking down people who have been exposed to infected people.
It has also started using text messages to seek updates from close contacts who have entered isolation, numbering about 1700.
"It is an honesty system but it is also an offence not to comply, and there are significant penalties," the minister said.
Stage two of national shutdowns was declared on Tuesday night by Prime Minister Scott Morrison in an effort to curb the spread of the disease.
Weddings will be restricted to the couple, celebrant and two witnesses only, while funerals can only have a maximum of 10 mourners.
Open house inspections and auctions are banned as are personal services such as beauty therapy, waxing, tattoo parlours and massage, to go with the closure of pubs, clubs, cafes and restaurants announced on Sunday.
Premier Daniel Andrews has backed the further closures and crackdown on social functions, telling people: "If you can stay home, you must stay home."
He said it was heartbreaking to see people lining up outside Centrelink offices to seek support after losing their jobs.
But the situation could be worse if people don't follow the restrictions aimed at slowing the spread of the virus, so the health system can cope.
"What we don't want is queues for people who need a machine to help them breathe. We cannot have people queuing for intensive care beds. That will mean they will die," he said.
"No dinner party, no shopping trip is worth a life."
The premier has also warned Victorians restrictions will become more severe, noting there had been an acknowledgement at the national cabinet on Tuesday that some states would have to ramp up measures faster than others.
About 500 police officers are tasked with enforcing the closure of non-essential services in Victoria and the mandatory 14-day self-isolation for travellers.
Individuals face fines of up to $25,000 and businesses could be forced to cough up $100,000 for breaching restrictions.