South Africans could have their power cut if more pressure is put on Eskom's grid this week, the power utility said on Wednesday.

"We are using our emergency reserves extensively so far this week," spokesperson Andrew Etzinger said.

"We can expect that these reserves will be depleted before the end of the week, which will mean additional pressure on the grid with the increased likelihood of load shedding."

This would affect the entire country.

On Monday Etzinger said there were no scheduled power cuts for the week. He said the system was tight but no load shedding was planned.

Last month, a coal storage silo at the Majuba power station in Mpumalanga collapsed, resulting in widespread power cuts. The silo held more than 10 000 t of coal and affected coal supplies to all six units at the power station.

Maintenance at the hydroelectric Cahora Bassa facility in Mozambique had also affected power supply.