South Africa's President Cyril Ramaphosa is returning home early from a trip to Egypt to deal with the "electricity crisis", a statement from his office says.
The flooding of power stations after heavy rains has exacerbated electricity shortages, which are having an impact on the economy. The cuts have halted gold and diamond production at some leading mines.
On his return on Wednesday, Mr Ramaphosa will be "briefed on plans to mitigate and resolve the current electricity crisis affecting most of the country".
He will also visit areas affected by flooding.
State-run power company Eskom said 6,000 megawatts of electricity - roughly 10% of the grid - was being switched off.
It said flooding at a coal mine and power station had disrupted supplies to homes and businesses.
Eskom is saddled with huge debts and is struggling to renew its ageing infrastructure.