UPDATED: Victoria is going into its sixth lockdown with the statewide snap closure justified by traces of COVID-19 found in wastewater at Wangaratta.
"We have a sewerage test that has detected COVID in the North-East," Premier Daniel Andrews said.
"The Wangaratta sewerage test has pinged, if you like, firstly positive, then it went negative and now it has gone positive again.
"We have some reason to believe there is COVID either in that community or has been in that community."
Mr Andrews confirmed the shutdown will start at 8pm on Thursday and last for seven days.
"We only get one chance to lockdown fast," he said.
"We can't change what has happened in the last few days."
The lockdown rules are "essentially the same" as Lockdown 5.0 which ended nearly two weeks ago.
"With suspected Delta cases infectious in the community, as well as a high number of associated close contacts and exposure sites, Victoria's Acting Chief Health Officer has declared stay at home restrictions will be reintroduced," Mr Andrews said in a press release.
"This means from 8:00pm tonight, there are only five reasons to leave home: getting the food and the supplies you need, exercising for up to two hours, care or care giving, authorised work or education if you can't do it from home, or to get vaccinated at the nearest possible location.
"Shopping and exercise must be done within 5km of your home or the nearest location.
"Face masks will remain mandatory indoors (not at home) and outdoors unless an exception applies - this includes all workplaces and secondary schools.
"Private gatherings are not permitted except for an intimate partner or nominated person visits. Public gatherings are not permitted. Exercise is limited to two people.
"Childcare and Early Childhood Care will remain open.
"Schools will close, with primary and secondary school students returning to remote learning, except for vulnerable children, and the children of authorised workers who can learn on site."
EARLIER: Victoria is on the brink of a sixth statewide lockdown just as the state was poised for a further easing of COVID-19 restrictions following the end of the most recent shutdown.
Just 24 hours after the state recorded a day of zero cases, Victoria had six cases of community transmission detected.
The fresh round of cases emerged from a school in Truganina in Melbourne's west and a community football match in West Footscray
There are no fresh cases in regional Victoria.
Health authorities released 15 new exposure sites on Thursday with eight listed as Tier One requiring those who attended them to urgently get tested and isolate for 14 days.
Three cases are connected to the traffic controller who worked at the Moonee Valley testing centre with the mystery cases being one from Maribyrnong and another is the Al-Taqwa College teacher and her household contact.
"Today's numbers are a reminder this virus hasn't gone away," Victorian health minister Martin Foley said.
"The situation we face is of great concern."
Mr Foley declined to comment on the possibility of a snap three day lockdown at this point.
"There are always discussions about how best to respond," he said.
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