The Auditor-General's office on Wednesday named and shamed departments guilty of irregular expenditure in the last financial year, with Defence being the worst offender.

That department racked up more than R1-billion in irregular expenditure, accounting for 43% of the government's total bill of irregular expenditure of just under R3,9-billion in 2009/10.

Lashman Kevish, a business executive in the AG's office, told Members of Parliament (MPs) that the Department of justice was second on the list, with R805-million, followed by the Department of Home Affairs in third place with R321-million.

In total, government departments accumulated R2,3-billion in irregular expenditure.

Almost one-half of that was owing to supply chain management irregularities, Kevish said in a briefing to the portfolio committee on public service and administration.

The presidency was guilty of just under R1-million in irregular expenditure but had the dubious distinction of featuring in all five categories of flawed tender and contract management specified in the Public Finance Management Act.

These ranged from failing to invite three price quotations for awarding contracts to suppliers who failed to provide valid tax clearance certificates.

Kevish said that 61 public entities made themselves guilty of a total of R1,589-million in irregular expenditure in the last financial year.

Here the three worst offenders were the Road Traffic Management Corporation with R360-million, the National Prosecuting Authority with R273-million and the Property Management Trading Entity with R264-million.

The State Information Technology Agency accumulated R214-million in irregular expenditure and CIPRO R95-million. In both cases the full amount was attributed to flawed procurement.

The department of trade and industry in July cancelled Cipro's controversial contract with ValorIT for an enterprise content management system due to serious allegations of tender fraud.

MPs described the figures cited by Kevish as "vast" and "frightening".

Public Service and Administration Minister Richard Baloyi said that government was committed to rooting out corruption and breaches of the PFMA.

It hoped to combat tender fraud in particular by placing all procurement on a central electronic database so that it could be accessed and scrutinised "at the click of a button", he added.

The minister rejected as alarmist a remark by the Democratic Alliance's Anchen Dreyer that the AG's figures were proof that the "wholesale looting" of state resources had placed South Africa on the brink of becoming a failed state.

Dreyer said the country did not need more anti-corruption units and regulations but for those already in place to yield results.

In a debate on corruption in the National Assembly on Wednesday, Finance Minister Pravin Gordhan said the perception that government lacked the political will to tackle it was false.