The volunteering programme in SCDF was first started in 1982 under the National Civil Defence Plan and Volunteer Scheme which provided an avenue through which residents can volunteer their service in civil defence roles within their local community. However, these volunteer residents were not expected to perform duties to the level that of a professional SCDF officer.
In response to the increased threat of terrorism following the September 11, 2001 attacks in New York, there was a growing need to enhance the civil defence capability of the country. As a result, a new form of volunteer organisation, the Civil Defence Auxiliary Unit, was created. Modelled from the Singapore Police Force’s Volunteer Special Constabulary (VSC) scheme of service, members of the CDAU are given the same status and authority of regular SCDF officers. They are expected to perform frontline operational duties alongside regulars. As volunteers, CADU officers are paid an allowance instead of wages.