The power grid was constrained, but stable on Monday after a spike in electricity usage as people returned from holiday, Eskom said.

"We are seeing a lot of demand, but we are able to supply. The risk of load-shedding is low to medium," spokesperson Khulu Phasiwe said.

"If things continue to go as they are, we are likely to go through this week without load-shedding. We ask people to use electricity sparingly."

He said there had been an average daily electricity demand of 25 000 MW since the start of the holidays, but this had now risen to 30 000 MW.

On December 29, the capacity available to meet the evening's peak demand was 30 094 MW (including open cycle gas turbines) with demand of 26 291 MW forecast.

Eskom said it expected 5 771 MW of outages because of planned maintenance and 8 029 MW of unplanned outages.

It called on people to reduce power use by 10% during the day to help it conduct planned maintenance.

On December 5, Eskom implemented stage three blackouts.

Stage one allows for up to 1 000 MW of the national load to be shed, stage two for up to 2 000 MW, and stage three for up to 4 000 MW.

On December 8, Eskom CEO Tshediso Matona denied that Eskom was in crisis.