NSW Treasury was established in April 1824 and is the oldest continuing government agency in Australia.

[4] In 2015, the Expenditure Review Committee of the state's Cabinet directed that public sector agencies (excluding state-owned corporations and authorities specifically approved by the NSW Treasurer) would, from 1 April 2015, operate as part of the Treasury Banking System.

This decision applied to all agency cash deposits held ‘at call’.

[5] The Treasury is led by its Secretary, Michael Coutts-Trotter who reports to the ministers listed below.

The Treasury is divided into six service groups that perform various functions on behalf of the department:[8]