Public Enterprises Minister Pravin Gordhan has described Mpumalanga as a crime scene in relation to allegations of looting at the power stations.
He said people with relentless greed had been involved in corrupt activities for the past few years.
He said they had been trying to fight corrupt elements in Eskom who collaborate with people from outside to steal and loot.
Eskom has a number of power stations in Mpumalanga and the energy availability factor in those stations has dropped.
Gordhan, who was appearing before the standing committee on public accounts on Wednesday, said they needed to fight corruption on all fronts.
He said he did not know if corruption was costing R1 billion a month in Mpumalanga.
The allegation emerged after former CEO André de Ruyter raised it in a television interview.
But Gordhan said he had not done the calculation on the scale of corruption at Eskom.
“Is Eskom corruption costing R1bn a month? I don’t know. I haven’t done the counting. But this is not a new revelation as I have indicated.
“I have stated publicly that Mpumalanga is certainly a crime scene. There are lots of actors, both outside of Eskom and within Eskom, who are collaborating to undermine the procurement and other processes, supply counterfeit parts, and do a poor job in terms of maintenance of units when they have outages. All of that is done to ensure they get more work at the end of the day and make more money.
“The relentless greed that drives people in this direction continues on an unmitigated basis,” said Gordhan.
He said there was also sabotage taking place in some of the power stations.
This included the sale of sub-standard coal to Eskom.
There was also the issue of the use of trucks to deliver coal instead of conveyor belts.
Damages were done to mills so that contractors will continue to get more work at Eskom, said Gordhan.