Eskom on Monday vowed to take disciplinary action against its workers who embarked on industrial action and damaged infrastructure last week as the power utility and unions failed to reach an agreement in protracted wage negotiations.

The National Union of Metalworkers of South Africa (Numsa) last week threatened to go on a massive strike at Eskom over the wage dispute, saying the state-owned electricity company was negotiating in bad faith. The National Union of Mineworkers (NUM), said it would only sign a deal if Eskom removed the precondition of disciplinary action.

But Eskom is not relenting, saying in a statement that those employees who engaged in potentially criminal acts of destruction of property and sabotage were now outside the company's jurisdiction and in the hands of the police. 

"The company has advised the unions to sign the wage agreement so as not to further prejudice Eskom employees who await their salary adjustments," Eskom said.

"It has further advised the unions that employees who participated in unlawful action will be subjected to disciplinary hearings and where found guilty of acts of misconduct, disciplinary action will be instituted against them."

"Eskom remains committed to concluding the wage negotiations expeditiously. The company urges all employees to honor their contracts of employment and the law and refrain from engaging in any further unlawful industrial action. The company is ready to sign and implement the wage agreement once all parties sign," it added.

The unions have requested a meeting with the minister of public enterprises Pravin Gordhan to try and break the deadlock, saying that they will not resume talks with Eskom without the meeting.