A fire broke out at Unit 2 of the Duvha power station in Mpumalanga on Monday morning, Eskom has confirmed.

In a statement, spokesperson Sikonathi Mantshantsha said the fire had been extinguished quickly and no injuries to staff had been reported. 

The extent of the damage was still being assessed.

No further details were given, except to say that the unit had been offline for a general overhaul since January this year.

Eskom has been battling theft, vandalism and sabotage as it struggles to keep the lights on. Late last month, theft and vandalism in Vanderbijlpark saw fire break out as two substations were targeted.

The cause of Monday's fire at Duvha is still unknown.

"Eskom is currently investigating the root cause of the fire, and the extent of the damage and the possible return to service," Mantshantsha said.