The series was originally intended to be set in St Kilda, with some of the sets constructed being replicas of the charge counter and Criminal Investigation Branch (CIB) room at the St Kilda police station. When the St Kilda City Council objected to the series and claimed that it would do great harm to the property values and image of the suburb, the series concept was changed and it was set in the fictitious suburb of Yarra Central.
95 Montague street South Melbourne Melbourne Victoria was the fictious yarra central police station building location. Today it has been pulled down and a new modern building is put up in it's place. On the Buildings a police station plaque was put up on the wall at the front entrance during filming of some series Episodes,Also the Studio Side Entrance in Jago Street Richmond of Channel 9 was used as South Yarra Central. a replica of the Actual St Kilda Police stations charge desk and Upstairs CIB including a picture hanging on the wall, corridors and doorways were created at GTV channel nine for the series.
Among the early titles considered for the series were "Saints and Sinners", which would have been appropriate for the St. Kilda setting of its early development, and "Police File", a title first used after the concept was changed, which Crawford Productions weren't happy with. In their search for another name, one of the titles suggested was "Department 24", a throwback to the successful Crawfords radio serial "D24", which had evolved into the television series Homicide (1964). A secretary preparing a list from the suggestions mistyped "Department 24" as "Division 4", a title that struck a chord when the list was presented, and was subsequently adopted as the title for the new series.