The Department of Treasury and Finance was formed on 1 July 2001 as a merger between the Treasury and State Revenue departments. On 3 February 2003, the Department also incorporated the functions of procurement management which had previously been the responsibility of the Department of Contract and Management Services.

The Department now operates in three broad functional areas:
providing economic and financial management for the State government;
collecting State revenue and administering the associated revenue laws; and
undertaking a central contracting and tendering function.