State electricity company Eskom said late on Sunday its power system remained constrained and would take up to ten days to recover from the effects of last week's wage strike.

Eskom warned consumers to work on the assumption that rolling power interruptions, or loadshedding, implemented over the last few days to ease pressure on the grid could still take place despite being averted on Sunday.

The utility was expecting staff to return to work on Monday after government and unions agreed to resume negotiations which had stalled over Eskom's decision not to award salary increases due to financial constraints.

At the weekend, the National Union of Metalworkers of South Africa said the zero percent proposal by Eskom was now "off the table".

"Eskom’s prognosis is that the power system will take up to approximately ten days to recover from the effects of the recent industrial action, once all staff return to work on Monday," the company said late on Sunday.

It said the strike had interrupted continuous processes at power plants, including coal management and transportation, which would now have to be cleared out and restarted, taking additional time. 

Labour unions are demanding a 15 percent increase for workers at Eskom, saying their members should not suffer for a financial crisis brought on by corruption and mismanagement by senior executives who have since been fired.