A resident at the Arcare facility in Maidstone, Melbourne caught the virus after a staffer worked while infectious, with another worker also testing positive on Monday.
The worst nightmares of the families of thousands of Melburnians housed in aged care facilities have been realised as authorities scramble to contain a COVID-19 outbreak.
The Liberal-National Opposition has pointed to several failures that have contributed to the latest shutdown, including the lack of a uniform QR system until Friday.
A Victorian Muffin Break worker has tested positive for Covid-19, forcing thousands more shoppers who visited Brimbank Shopping Centre in Deer Park in Melbourne to quarantine.
A staff member from Arcare aged care facility in Maidstone, in Melbourne s north-west, became infected with Covid-19 after working at Blue Cross aged care in Sunshine.