Southern District Command Centre deployment co-ordinator Dave Scott said a vehicle belonging to Renee Lisa Barrett (42) was located at Kelvin Heights; however, she had not been seen for "at least a couple of days".
Ms Barrett had medical conditions and both police and family had concerns for her safety.
The operation began at Kelvin Heights last night with police canvassing the neighbourhood and conducting an aerial search around Kelvin Heights.
Anyone with information or sightings of Ms Barrett could contact Southern Police on 03 4411622.