Authorities said they had gained control of the cluster in Melbourne, which has produced 19 cases.
Officials said no additional locally acquired cases were found on Wednesday.
But Victoria’s government is under pressure to explain how the virus escaped hotel quarantine, after similar breaches nationally in recent times.
Victoria’s cases all stemmed from a hotel worker who unknowingly caught the UK variant of the virus and carried it into the community.
Victorian Premier Daniel Andrews defended the “short, sharp circuit-breaker” lockdown, saying it had safeguarded against a potential local third wave.
“There was simply no alternative but to follow the advice provided,” he said.
“I am very proud of every single Victorian for the work they’ve done, and the sacrifices they’ve made.”
He did not say whether spectators would be allowed to return to the Australian Open tennis tournament in Melbourne for the finals week.
Mr Andrews said officials had traced 3,400 close contacts of people who had been infected.
Schools, churches and all non-essential shops have been shut across the state since Saturday.
The state’s six million residents were barred from leaving their home except for exercise, shopping, caregiving and essential work.
Some restrictions will remain after the lockdown, including limits of five visitors per household and mask-wearing in packed indoor spaces. Workplaces can have up to half of their employees return.
Prior to the outbreak, Victoria – Australia’s second most populous state – had not seen a local infection for 28 days.
The state had already endured two previous lockdowns – including a four-month shutdown of its state capital Melbourne – due to failures in the hotel quarantine scheme.
Mr Andrews emphasised the “hyper-infectious” nature of the UK variant as justification for announcing the lockdown last Friday.
But some experts – including the Australian Medical Association – have been calling for a review of hotel quarantine environments due to concerns about airborne transmission.
Victoria is now considering a purpose-built quarantine facility.
Australia has reported over 29,000 cases and 909 deaths since the start of the pandemic – far fewer than many nations.