Swiss Engineering firm Asea Brown Boveri (ABB) says it has put aside $325-million (about R6-billion) as a provision to cover costs related to corruption probes at Kusile power station.

On Friday, the Zurich-headquartered firm said it was cooperating fully with the authorities and "hopes to reach a final settlement with them in the near term".

ABB won a R2.2-billion contract for work at Kusile in 2015. Its subsequent subcontracting of some of the work out to a company called Impulse International is being probed by authorities.

In July, two former South African ABB employees and their wives were arrested in connection with kickbacks allegedly paid by Impulse to ABB for inflated contracts.

ABB South Africa has already paid back R1.56-billion as part of a settlement reached in 2020. At the time, it warned that it may have to pay more based on further reviews of its work at Eskom.