State-run power utility Eskom said on Tuesday external auditors had raised "two reportable irregularities" with their regulatory body related to an obscure company and the reinstatement of former CEO Brian Molefe, who has since left.
Eskom, which earlier postponed its annual results presentation scheduled for Tuesday, said in a statement it "had 30 days to take appropriate steps to mitigate the risks identified."
Company spokesperson Khulu Phasiwe said one of the irregularities related to another former acting chief executive, Matshela Koko, who allegedly violated procurement rules by giving contracts to a firm where his stepdaughter was a director.
"The Board has finished its investigation and the matter is now with the Minister of Public Enterprises Lynne Brown, who is applying her mind to the matter," he said.
Eskom, which provides virtually all of the power for Africa's most industrialised economy, has lurched from crisis to crisis as it tries to build new power stations.
In late June the company appointed Johnny Dladla as acting chief executive, a stopgap measure after a leadership vacuum at the company worsened when the chairman abruptly resigned.
Dladla replaced Molefe, who was briefly reinstated and then removed in May by a team of government ministers amid growing concerns about governance at Eskom.
Eskom has also come under scrutiny in the media after leaked documents put it at the centre of allegations of improper dealings in government contracts by the Guptas, business friends of President Jacob Zuma. Both Zuma and the Guptas have denied any wrongdoing.