Two of the three new carriers came into contact with the virus at two different hospitals in Seoul, including the Samsung Medical Centre, one of the epicentres of the outbreak, the health ministry said.
The third case was a family member of another patient, AFP reported.
Separately, a 39-old woman who had been infected with the virus and recovered gave birth to a baby at Samsung Medical Centre on Tuesday, Yonhap news agency said.
Of the 175 confirmed cases, 27 have died, 54 have recovered and been released from hospital and 94 are still being treated. Of them, 16 are on life support.
Some 2,805 people are still under quarantine, down around one quarter from Monday.