Melbourne lockdown

From 11:59pm tonight, all of Victoria will return to stage four lockdown restrictions, meaning there are only four main reasons to leave the home: shopping for essential supplies, care and caregiving, exercise and essential work.

Exercise and shopping will be limited to within 5 kilometres of the home.

Face masks will need to be worn indoors and outdoors and no visitors will be allowed in homes.

Premier Daniel Andrews said 671 new coronavirus cases had been detected since yesterday and seven more people had died.

Six of the deaths have a connection to aged care.

Andrews said there was an "unacceptably high" number of community transmission cases, and the state had 760 active "mystery" COVID-19 infections where the source of the transmission was not known.

"Those mysteries, that community transmission, is in many respects our biggest challenge and the reason why we need to move to a different set of rules," he said.