Possibilities on RZ4 zoning in Canberra

I have come across a property with RZ4 zoining. I have been given mixed advice on this and wanted to know from someone with information on this zoining. From my understanding though it is a residential zoning, we may be given permission to run a medical practice or child care centre. Would the permission be given as case by case evaluation or it should not be a problem with that particular zoning to run a medical practice? On the other hand I have been told that we need to apply for lease variation and that it is very difficult to get permission for commercial use. Any information on this is much appreciated.