Eskom is warning rolling blackouts could move to a higher stage after protests at some of its power stations.
Power cuts are currently at Stage 2.
The utility says some of its employees have embarked on unprotected strike action.
It follows a deadlock in wage negotiations.
Eskom says roads have been blockaded, and employees who continue to work are being intimidated.
It’s appealing to unions to respect the law and desist from illegal conduct.
The alleged illegal acts have been reported to the police.