Four new COVID-19 cases have been uncovered among a family in Melbourne’s north, sparking a search for the source of the outbreak.
Health Minister Martin Foley confirmed two more people had returned positive coronavirus test results, on top of the two cases revealed earlier on Monday.
Health authorities were alerted to the unfolding cluster when a Whittlesea man presented for testing on Sunday after developing symptoms on Thursday.
He and another man, a male relative from a separate household, both tested positive.
A woman and pre-school-age child living with the Whittlesea man have also since been confirmed as COVID positive.
Other family members among the two households are also in isolation and have so far tested negative.
Highpoint Shopping Centre in Maribyrnong and a Bundoora swimming school have been listed as initial exposure sites.
Anyone who attended the “tier one” sites at specific times on Thursday and Friday must get tested and isolate for 14 days regardless of the result.
Victoria’s Chief Health Officer Brett Sutton said test results indicated the Whittlesea man is carrying a high viral load and could have infected casual contacts.
“He is likely to be quite infectious,” he told reporters on Monday.
“We have to ready ourselves for any other positives and when there are close contacts who do become positive, that raises the possibility that even a casual contact could become positive as well.”
Mr Foley said there was no indication the COVID-positive family members were linked to any exposure sites visited by a Victorian man who contracted coronavirus in hotel quarantine in South Australia.
The department last week admitted it had listed the wrong supermarket as an exposure site during the outbreak earlier this month.
People had been warned of potential exposure at Woolworths in Epping a fortnight ago.
That advice was corrected on Friday after it was discovered the man from Wollert in Melbourne’s north had actually shopped at Woolworths in Epping North, three kilometres away.
Mr Foley said the Whittlesea man’s infectious period potentially started on May 18, well after the COVID-infected returned traveller re-entered hotel quarantine.
“We do not rule out the prospect that there is a link,” he said.
“The dates do not line up immediately so we cannot rule out if there is a missing link out there.”
He added genomic sequencing results, expected as early as Tuesday, may help establish the origin of the cluster.
In the hunt for a potential missing link, Mr Foley urged anyone with symptoms to come forward for testing, with opening hours extended across major Melbourne sites until 8pm on Monday.
Earlier, Opposition Leader Michael O’Brien said it was clear the government had stuffed up contact tracing.
“If we get another outbreak in Melbourne because this government didn’t do the basics right then frankly, the health minister and other ministers need to lose their jobs,” he said.
The four new cases snap Victoria’s 86-day streak without a locally acquired case, with Mr Foley saying a degree of complacency had emerged.
Australia’s Chief Medical Officer Paul Kelly said it was a stark reminder of the need for people to get vaccinated.
“We are approaching winter very quickly,” he told reporters in Canberra.
“We’ve been in a very good position this year in terms of acquired cases in Australia but that can change very quickly.”
Meanwhile, police have begun a two-week compliance blitz to ensure public transport users wear masks after a drop-off in compliance rates on Melbourne trains and trams.
Police officers from Monday are targeting train stations and tram routes, issuing penalties up to $200 to those who decline an offer of a mask.