Three Melbourne aged care homes are in lockdown after a resident at each centre tested positive for coronavirus.
Another facility has also been locked down as it awaits test results for two residents.
A resident at Lynden Aged Care at Camberwell was diagnosed with the virus while being treated at a metropolitan hospital, prompting the facility to shut its doors to visitors on Tuesday.
The resident remains in hospital, while the 177 residents and staff at the aged-care facility have been tested for the virus.
"We want our residents, their families, our dedicated staff and our community, to be aware of this situation and to reassure everyone we are working tirelessly to protect our residents and staff," chief executive Carolyn Panassie said in a statement.
Close contacts of the infected resident have been ordered to quarantine at home, the Department of Health confirmed
HammondCare's Caulfield Village went into lockdown after a resident in its dementia ward tested positive on Monday, before a second swab came back negative on Tuesday.
Victoria's Deputy Chief Health Officer Annaliese van Diemen said all positive tests are treated seriously, with the facility managed as if it were an outbreak site while further testing is undertaken.
"A subsequent negative test doesn't negate the first positive test," she said on Tuesday.
HammondCare senior nurse Angela Raguz said the centre's priority was to care for the resident and protect 11 others in the dementia ward.
A family visit is not believed to be the source of the possible infection, Ms Raguz said.
It follows a similar situation at the Villa Maria Aged Care Home at Bundoora, where a resident who was taken to hospital at the weekend with a fever returned an inconclusive test result.
A subsequent test showed the resident did not have COVID-19.
The facility is in lockdown and the resident is isolating in their room as they await the result of two more tests.
Residents and staff at all three aged care homes will be tested for the virus while contact tracing is under way.
Meanwhile, two residents at MiCare facilities Margriet Manor and Overbeek Lodge, both in Kilsyth, have been tested for coronavirus after showing "flu-like symptoms", the facility's chief executive Petra Neeleman said in a statement.
The facilities are in lockdown as MiCare awaits the results.
"Over the past two months, MiCare has tested approximately one dozen residents for COVID-19, immediately notifying residents, families and staff and implementing additional temporary, precautionary visitor restrictions," Ms Neeleman said.
"All the results to date have been negative."
Seven people tested positive to coronavirus on Tuesday, with the state's total number of infections at 1573. About 120 cases are active.
A new case has been linked to the Cedar Meats outbreak, with the total number in the cluster at 100, the health department confirmed.
One case of a returned traveller in hotel quarantine and three other cases are under investigation.
Authorities have also removed one case from the overall tally after reclassification.
An ongoing inquiry into the state government's response to the coronavirus has also revealed there had been 5604 fines related to breaching restrictions issued by Sunday, for a total of more than $8 million.
Police Minister Lisa Neville said that was a "pretty good balance" considering more than 45,000 spot checks had been conducted.
Australian Associated Press
