The state utility firm said it was implementing stage four load shedding, or scheduled blackouts, after it lost 4,000MW following the loss of two power units.

“Regretfully, Eskom has just been forced to implement Stage 4 load shedding at 07:20 following Majuba Unit 5 and Tutuka Unit 4 tripping,” it said on Twitter.

On Sunday, Eskom announced Stage 2 load shedding when it lost 2,000MW of power supply after the tripping of other generating units.

Poor maintenance, rising costs, falling revenues, crumbling infrastructure, corruption and mismanagement have in the past been blamed for South Africa's energy crisis.

Eskom has since apologised, describing the power system as unpredictable on Twitter.