The Democratic Alliance's Raenette Taljaard has urged President Thabo Mbeki to act decisively against corruption, saying his government lacks sound ethics, moral authority and a political will to act.

"Sweep away the cobwebs of corruption and conflicts of interest that plight this government," she said on Monday, in reply to Mbeki's state of the nation address.

"Failure to act will see a false dawn to the 'second decade of freedom' and render it a freedom deferred."

Taljaard, the DA's finance spokeswoman and a former representative of the watchdog public accounts committee, said the president had on Friday emphasised the need for moral renewal, but all the public saw at the opening of Parliament was "moral and ethical turpitude".

"They see a motley crew under investigation while the new South Africa is under construction.

"They see at least four people brushing with the law or grabbing the limelight due to corruption charges and/or criminal investigation."

These included former African National Congress chief whip Tony Yengeni, ANC Women's League president Winnie Madikizela-Mandela, and Deputy President Jacob Zuma.

There was also New National Party leader, and Western Cape premier, Marthinus van Schalkwyk, whose own party members accused him of knowing about a R300 000 donation from the developer of a golf estate development.

"What type of society are we and what values do we embody when the presidential ceremonial entourage at the opening of Parliament resembles an identification parade at a criminal investigation?" she said, although the comment was later retracted.

Yengeni has been convicted of fraud and has misled Parliament; Madikizela-Mandela has been on trial for fraud and theft; and Zuma is facing allegations of allegedly soliciting a R500 000 bribe from a company involved in the arms deal.

Taljaard said at least three Cabinet members had been implicated or had been under investigation for suspected corruption since the ANC came into powerformer defence minister Joe Modise, former transport minister Mac Maharaj, and Zuma.

There were a number of other instances of irregularities in the public service, including claims against Civil Aviation Authority CEO Trevor Abrahams, and the housing scandal involving Spoornet CEO Zandile Jakavula.

"It is clear that when the corruption circus rolls into town, and not only into the maladministered ANC-run Eastern Cape, everyone wants to get in on the act.

"But, instead of having an iron-fisted approach of cracking down on corruption or dubious practice, most of these cases were dispensed by a limp-wristed wrap on the knuckles or inaction," she said. 

With acknowledgements to Sapa.