Five cases of COVID-19 have now been linked to a growing cluster of COVID-19 at the Centenary Hospital for Women and Children.
A baby is among the new positive infections which also include a staff member and two visiting carers.
It comes after the initial case was detected in a baby in the Special Care Nursey on Tuesday night.
How the first baby became infected with the virus remains the subject of ongoing investigation.
The new infections are among 41 cases of the virus reported in the ACT on Thursday.