The electricity supply is expected to be constrained during the week, Eskom said on Monday.
“There is no scheduled load shedding at this stage, but the second half of the week is expected to be very tight,” said spokesman Andrew Etzinger.
Eskom’s diesel generators were under pressure because of a lack of fuel.
“Diesel supplies are a concern due to volumes received not meeting our requirements. We are working with suppliers to unlock the constraints,” said Etzinger.
On Sunday, Eskom declared a power emergency with large industrial customers. It also implemented rolling blackouts at the weekend.
Eskom said the power system had experienced an increase in demand as a result of weather conditions and increased load losses as a result of multiple tripping of generating units at the Majuba and Matimba power stations.
The power utility had lost a total of 1700MW of generating power, it said on Sunday.
Etzinger said the risk of blackouts on Monday and Tuesday was medium to low.
“This is owing to steady progress made in building reserves to limit the risk of load shedding next week,” he said.