Embattled power utility Eskom said in an update on Friday that the country's power supply was "extremely constrained" and the risk of load-shedding was high for later in the day.

The power utility implemented stage 2 rolling blackouts overnight on Thursday due to power generation units being lost earlier in the day.

Load-shedding was halted at 5am on Friday. Eskom has been relying on open cycle gas turbines, which consume diesel, and pumped water storage schemes to keep the lights on while dealing with plant breakdowns. 

“We did last night’s load-shedding so we could replenish those emergency reserves. We are looking better for today, but the system is quite constrained,” said Eskom spokesperson Dikatso Mothae.

But in an updated statement issued later the outlook was more bleak.

"While the system remains extremely constrained and vulnerable, the overnight load-shedding assisted with partial recovery of our emergency resources to enable us to get through the morning," read the statement.

"We will need to continue to replenish both our water levels at pumped storage schemes and diesel for our open cycle gas turbines over the weekend in order to place us in a better position to stabilise for the week ahead.

"Our objective remains not to implement load-shedding during the day today, however given the unplanned breakdowns that are still above 10,500 MW and the need to continue to replenish emergency reserves, the probability of load-shedding remains high for the latter part of the day but will only be implemented if absolutely necessary."

Mothae urged customers to use electricity sparingly.