The board of Eskom says it will investigate allegations of corruption and victimisation against the power utility's chief operating officer Jan Oberholzer.
Eskom says it has received allegations from the society organisation Corruption Watch and the South African Federation of Trade Unions (Saftu) against Oberholzer.
"Both organisations cite the same source, an Eskom employee who has since deposed to an affidavit to the Commission of Inquiry into State Capture, as having raised the allegations."
The Corruption Watch and Saftu want the Eskom board to intervene and protect the whistleblower.
Many of the allegations raised in the letters have not previously been made available to the executive management and the board of Eskom.
The new allegations follow on a report in the Sunday Independent that accused Oberholzer of holding shares in a company that held a contract with Eskom.
"Eskom has previously dealt with matters concerning the employee in question, and after an investigation led by an outside senior counsel, the investigation was closed following a thorough examination of the allegations, to which no substance was found."
However, in light of the new allegations contained in the letters, including the alleged abuse of power, the board has taken urgent steps to address these allegations in what it says is a transparent process following Eskom's governance principles and disciplinary codes.
The board has engaged the services of an independent senior counsel to investigate the allegations against the COO. Once the probe is concluded, recommendations will be made to the board.
"It is hoped that the conclusion of such an investigation, together with any subsequent actions that may be required, will bring about a fair and lasting resolution to the matter for all parties concerned," said Eskom.
Fin24 approached Corruption Watch to enquiry about the nature of the allegations and was told that the organisation regards the issue as a private matter on which it is not commenting on to the media.
"We are in correspondence with Eskom and it would be up to Eskom to decide if it wants to provide the media with more detail about the allegations or not," Fin24 was told.