Victorian authorities remain nervous about the potential for undetected coronavirus cases, despite 26 days with no new cases.
Health Minister Martin Foley said despite the state now having no active cases, Victoria was sticking to the national strategy of suppression rather than eradication.
"The way in which this highly infectious virus spreads and the way in which so many people who can be positive but show no symptoms of the virus makes us all work on the basis that it is still out there," he said.
Premier Daniel Andrews is likewise unconvinced that Victoria is coronavirus-free.
"I think there's every chance that there are a handful of cases out there. This is a wildly infectious virus," he said.
"Even 26 days in a row of zeros, that's not a vaccine."
As the state's borders with the rest of the country open up, 16,409 people have been tested in Victoria over the previous 24 hours.
Mr Andrews also said on Wednesday that Victoria's overhauled hotel quarantine system would be thoroughly stress-tested before it reopened on December 7.
Hotel quarantine staff will not be allowed to have other paid work, to try and limit the spread of COVID-19, and some staff may even live on-site.
Their close contacts will also be mapped out in case of any infections.
But Mr Andrews warned no model could be zero risk.
"There will be a whole lot of walk-throughs and trials, and all manner of work that's done to prove up that model and make sure that it's as safe as it can possibly be," he said.
The state's second wave of the virus spread from its hotel quarantine system, and was responsible for more than 18,000 COVID-19 infections and 750 deaths.
Victoria's revamped quarantine program for international arrivals will cater for 160 returning travellers per day, or 1100 per week.
"We'll have an exclusive workforce. They can only work for us - they won't have any second jobs," the premier told the ABC on Wednesday.
"We'll advance contact trace all those staff, so we know who they live with, what the people they live with do for a living - so we don't have someone sharing a house, for instance, with someone who works in an aged care facility," he said.
A judicial inquiry into Victoria's botched hotel quarantine program has handed down its interim findings and will issue its final report by December 21.
Queensland and SA will reopen their borders with Victoria on December 1, while the NSW-Victoria border reopened at midnight on Monday.
Virgin will restart flights from Melbourne to Queensland on Monday.
Flights from Melbourne to the Sunshine Coast will resume from Monday, and flights to Cairns from December 17.
The airline says it will have 38,000 seats on flights between Victoria and Queensland by Christmas.
Australian Associated Press