The National Union of Mineworkers (NUM) and National Union of Metalworkers of South Africa (Numsa) on Tuesday officially rejected Eskom's zero percent wage offer, saying that the state-owned power utility cannot plead poverty because it was "dealing with a self-imposed crisis".

Last week, wage negotiations at Eskom collapsed after unions walked out, saying the power utility was negotiating in bad faith. The unions are demanding a 15% wage increase across the board and R2 000 housing allowance, among other demands. 

"We met yesterday and our revolutionary consciousness makes us recognise that without the unity of workers we can never achieve our goals. It is for this reason that we have taken the decision to put aside our political differences and to unite against a common enemy whose agenda, is the super exploitation of workers at Eskom," the unions said in a joint statement. 

"We will exhaust all options available to us legally before resorting to go on strike. We have scheduled pickets during lunch time in different parts of the country where workers will demonstrate their disgust with Eskom for their provocative stance."

The unions said that there would be a big demonstration taking place at Eskom's headquarters Megawatt Park at lunchtime on Thursday while union officials have demanded an urgent meeting with the Eskom board, energy minister and the President.