South Africa's state power utility, Eskom, said on Tuesday that it will have to execute "Stage 6" cutbacks to prevent countrywide blackouts.
Stage 6 means that South Africans will now experience multiple cuts per day, each lasting between two and four hours, on a rotational basis.
Eskom, which generates more than 90 percent of the country's energy, has been hit by strike action over wages since last week.
Workers walked out, demanding a 15-percent pay hike.
"Eskom is in this position because of the industrial action which has meant that in many power stations up to 90 percent of the staff could not attend to the duties... because of intimidation," State Enterprises Minister Pravin Gordhan told a media briefing shortly after the ramped-up rationing kicked in.
The blackouts are "causing huge amount of damage to South Africa's reputation", Gordhan added.
Africa's leading industrialized country last experienced such drastic outages in December 2019.
Power cuts are a major source of frustration and discontent in South Africa, where protests broke out near Eskom's offices last year.
Unions on Tuesday announced they have made "considerable progress" in wage negotiations, and urged Eskom workers in a statement "to normalize the situation".