South Africa's electricity provider Eskom said no load-shedding was expected for the rest of the week as their emergency resources have been used to ensure that there was adequate generation capacity to meet the demand, but warned that the risk remained.

"Despite a constrained and vulnerable system, no load-shedding was implemented [on Wednesday] today. Our emergency resources, namely the open cycle gas turbines and pumped storage schemes, were used cautiously today in order to ensure that they remained at adequate levels to supplement capacity for the rest of the week," the power utility said in a statement on Wednesday night.

"All three units that were on unplanned outage as a result of the flooding which caused coal handling problems are all back in service but not at full capacity. Two reliable and major generating units will go on scheduled maintenance [on Thursday] tomorrow, and we have planned accordingly to ensure that their absence does not destabilise the system."

The state company - which supplies about 95 percent of South Africa's electricity, most of it coal fired - said the unplanned outages or breakdowns were at 11 780MW at 5.30pm on Wednesday, adding that their teams continued to work around the clock to reduce the incidents of breakdowns in order to increase available capacity.

Eskom was forced to effect load-shedding last year, suppressing electricity demand on a rotational basis to avoid overwhelming the grid as its generation units broke down largely due to years of inadequate maintenance.

Generally, Eskom has applied "stage 2" load-shedding which involves suppressing up to 2 000 megawatts of demand, but last year it was forced to accelerate this to an unprecedented "stage 6" as the grid came under immense pressure.

"It is important to note that the power system is vulnerable and volatile with an ageing fleet that requires higher levels of maintenance. However, getting back to stability will take some time and we request our customers to work with us by reducing their demand while we work on improving the effectiveness of our maintenance," Eskom said.

"We are monitoring the system closely and we will continue to give periodic updates on the status of the power system as things may change at short notice."

On Tuesday, Eskom dismissed as inaccurate a news report suggesting municipalities had been told to brace for an imminent escalation of rolling blackouts to "stage 8", saying that while there was a plan in place for such an occurrence, it was unlikely.

Eskom said in keeping with its obligations in terms of the Disaster Management Act it was required to develop contingency plans for identified major incidents. At the time, Eskom warned that the power system was under pressure following heavy storms and rains in Mpumalanga province which had caused disruption to coal supply overnight.