South Africa's Eskom has managed to restore eight units at power plants after implementing its highest stage of controlled power cuts early on Sunday, the power utility said after multiple failures at Majuba and Camden power stations over the weekend.

On Saturday, Eskom applied Stage 3 power cuts, known locally as load-shedding, effectively cutting 3,000 megawatts to the national grid.

"Of the 10 units that we lost overnight, we have essentially returned six units," Eskom group CEO Dan Marokane told reporters on Sunday.

He said five to six units were expected to become operational during the day, bolstering the 3,200 MW of capacity recovered overnight.

"We anticipate to get out of this stage by the end of the week," he said, adding that given the pace of recovery, Eskom would consider dialling down its power cuts by Monday.

Early on Monday morning, Eskom said the power outages would be reduced to Stage 4 until further notice.

Regular breakdowns at Eskom's fleet of ageing coal-fired plants, providing the bulk of electricity in Africa's most industrialised economy, are often the cause of load-shedding - an incremental system where Stage 1 sees 1,000 MW cut from the system, with Stage 6 the highest implemented to date.