Premier Daniel Andrews confirmed the state's "circuit breaker" lockdown will lift just before midnight on Wednesday, after the state recorded no new COVID-19 cases.

But he refused to rule out further lockdowns until at least 90 per cent of Australians were vaccinated.

"I can provide no guarantees because I'm not prepared to pretend to the Victorian community that this is over," he said.

"We've got one pallet of vaccines turned up - that's great news. But we haven't got any in anyone's arms yet. That's a process.

"Some might see that as the moon landing. I think it's the start of the end."

From 11.59pm on Wednesday, Victorians will be able to leave their home for any reason, and the five-kilometre travel limit will not apply.

Masks will remain mandatory indoors and outdoors when physical distancing isn't possible, while home gatherings will be limited to five visitors, down from 15. Public outdoor gatherings are also limited to 20 people, down from 30.

Closed retail and hospitality businesses, gyms, community facilities and entertainment venues can reopen, while religious gatherings and ceremonies will also be able to resume, subject to density limits.

Students will return to school on Thursday, while public and private sector offices can reopen with up to 50 per cent of capacity.

Fans will also be able to return for the final days of the Australian Open tennis tournament, with crowds at Melbourne Park to be capped at 50 per cent capacity.

The new suite of restrictions will remain in place until February 26.

Victoria's five-day lockdown was announced on Friday amid fears the highly-infectious UK strain of COVID-19 had spread from the Holiday Inn quarantine hotel at Melbourne Airport into the community.

The outbreak now stands at 19 cases, while more than 3400 close contacts remain in isolation.

A resident at Reservoir's Twin Parks Aged Care Centre has returned a weak positive following two negative tests.

The man was confirmed to have had the virus last year.

The health department on Wednesday afternoon said it was thought to be a case of viral shedding.

The result has not been included in the latest testing numbers and the man would be tested a fourth time.

All staff and other residents at the centre had been tested as a precaution, the department said.

It came after Chief Health Officer Brett Sutton warned positive cases were still likely to emerge from contacts in isolation.

"The incubation period is 14 days. There are literally thousands of people who've been potentially exposed to infectious cases. They need to see out their quarantine period. They need to not be complacent," he said.

Professor Sutton defended the lockdown, noting 66 close contacts were identified for each Holiday Inn case on average, while there was an "explosion" in the number of exposure sites.

"The great dilemma of public health and our great frustration is that when something doesn't happen, you get the accusation that you've done something that wasn't necessary," he said.

Opposition Leader Michael O'Brien said the state could not afford to keep going in and out of lockdown due to hotel quarantine failures.

"We need to keep Victoria open. There's one way to do that; good hotel quarantine, good contact tracing, proportionate responses," he told reporters.

Meanwhile, the government's plan to extend its state of emergency powers is looking in doubt after negotiations with key upper house crossbenchers failed.

Reason Party leader MP Fiona Patten said in a statement on Wednesday she would vote against the bill and urged the government to bring forward legislation specific to the pandemic.

A record 39,258 test results were received in the 24 hours to midnight on Tuesday. There are 25 active cases across the state.

Australian Associated Press