Health Minister Martin Foley has revealed in a Wednesday morning press conference that three people who previously had coronavirus have retested positive again after leaving isolation.

The cases were deemed as shedding and have not been included in yesterday’s numbers, which have been described as another “doughnut day” of zero cases and zero deaths across the state.

Two of the cases are in metropolitan Melbourne and one has recently flown to South Australia.

“So, in an abundance of caution, both jurisdictions have decided to align their public health advice this morning,” Mr Foley told reporters.

“This means that the top of health risk potential exposure sites are at both the Melbourne Central and Melbourne Airport.”

There will also be an alert issued for the airport in South Australia which the positive case flew into and anyone with symptoms should get tested.

There are now four active cases across the state and two people are in hospital.