The Commonwealth parliament's Public Accounts Committee (PAC) was established in 1913 and to the end of 1995 had produced 397 reports on government expenditure and administration, with almost all its recommendations implemented by government. However despite the Committee's prominence among the instruments parliament has used to oversight the executive, not only does it lack clear legislative authority for major areas of its activities but its specific purpose is not defined in its legislation. Among other things the latter omission renders proper evaluation of the PAC's effectiveness impossible, as objectives are a necessary prerequisite to assessment. This thesis establishes the de facto purpose of the Committee by tracing the development of standing public accounts committees generally, and by analysing the PAC's work as shown by its output of tabled reports. In that development, six evolutionary phases are identified: the PAC's roots in the move to a parliamentary control of the administration of government expenditure in Britain from the 1780s; its genesis in the 1850s with the concept of the standing public accounts committee, to be concerned with regularity and probity in government expenditure; its origins in the establishment of the British standing public accounts committee , in 1861, stressing high standards of government accounting, audit and reporting; its establishment in the Commonwealth, concentrating on information on departmental activities, efficient implementation of government programs and provision of policy advice; its re-establishment in 1951, stressing parliamentary control of government financial administration; and its operations from 1980, pressing for economic fundamentalist change in the public sector. Their output shows that in these phases the committees concerned displayed characteristic standing public accounts committee activism and independence in utilising the wording of their enabling documentation to adapt themselves to changes in their environment by pursuing a corresponding different mix of one or more of the following concurrent immediate aims: ensuring adequate systems of government accounting, audit and reporting; ensuring probity and regularity in departmental expenditure; obtaining and disseminating information on departmental activities; ensuring high standards of departmental administration and management; providing policy advice to executive government; and ensuring economic, efficient and effective government spending. Together these attributes and practices have made the PAC a parliamentary instrument of unequalled flexibility with a single continuing underlying aim - a purpose not concerning the public accounts per se, but directed at achieving high standards of management and administration in government by calling the Commonwealth's public service to account for its expenditure and activities.