The National Union of Mineworkers referred a wage dispute with Eskom for mediation on Wednesday, it said after the company announced a R3.6-billion net profit for the 2009/10 financial year.

"It is totally ridiculous that a parastatal that received a whopping 24.8 percent [increase] in tariffs can give its workforce a meagre 5.5 percent," a union statement read.

It wanted to know how workers were supposed to afford electricity with that increase. The union wanted an 18 percent increase and a housing offer, to proceed with its three-year agreement.

"The National Union of Mineworkers calls on Eskom to exercise caution and common sense and to be sensitive to workers' demands," said Paris Mashego, negotiator for Num at Eskom.

"The executive get lots of money and housing allowances as if they are entrepreneurs who have invented electricity."

The company said its profit compared with a R9.7-billion loss in the previous financial year. This was partially attributed to the sale of more electricity, and the tariff increase.

It had secured a government guarantee of R176-billion and had used R117-billion. They would use remaining R59-billion to "firm up" their credit rating.

The company recently experienced a severe crisis with unpredictable electricity supplies due to a combination of increased demand for power, and infrastructure neglect.

Asked at Wednesday's results presentation about the NUM's discontent, Eskom's acting chairman Mpho Makwana said it was premature to comment.

"We are still negotiating and we can't predict the NUM's intentions."