The board of the Passenger Rail Agency of South Africa (Prasa) has roped in the Special Investigating Unit (SIU) to probe allegations of ghost workers, fraud and the "sabotage" of tenders at the institution.

At a meeting on Tuesday, the board said "corruption will not be left unattended".

The board said it received a preliminary report on the matter and that there was "clear prima facie evidence" of wrongdoing.

It added that the SIU would also probe allegations that insurance companies had been defrauded, with the view of recovering misappropriated funds and carrying out lifestyle audits. The SIU is also expected to investigate claims of infringements of supply chain management processes by employees.

The board said the probe would not be limited to members of supply chain management committees.

"The board has received unpleasant reports that there are deliberate attempts to sabotage the awarding of critical tenders which will unlock modernisation and alleviate unemployment and poverty," Prasa said in a statement.

The board may include other "irregular matters in the SIU's mandate", it added.

"Prasa employees are encouraged to cooperate with seconded members of the SIU to ensure expediency and finalisation of these matters. All efforts are to restore Prasa's mandate of offering affordable and better services to the people of South Africa," the board said.