The union came was established on 1 July 1994 with the amalgamation of the Public Sector, Professional, Scientific, Research, Technical, Communication, Aviation and Broadcasting Union (PSU) with the State Public Service Federation (SPSF).

Starting with the decision of the High Court in the CYSS case[7] (1983) (on the extent of the conciliation and arbitration power), it appeared that these constraints were eroding.

The primary exception is the Victorian Branch which operates completely in the National System since Victoria referred the industrial relations power to the Commonwealth Government in 1996 by the then Premier Jeff Kennett.

The PSU group also includes members employed in businesses previously part of the Australian public sector, prior to privatisation (e.g. Telstra, CSL).

The PSU group was formed through the amalgamation of a number of public sector unions in the late 1980s and early 1990s, including: