Stage 2 load-shedding will be implemented from 3pm, Eskom has said.
Eskom spokesperson Khulu Phasiwe tweeted an update at 2:30pm. No further details were given.
Earlier in the day, the power utility said stage 1 load-shedding would be implemented from 11:00am until 23:00pm.
"This is due to plant breakdowns, resulting in an imbalance between supply and demand. Please visit the websites of your electricity providers for a list of which areas will be affected," Eskom said.
Stage 1 allows for up to 1 000 MW to be shed from the grid. Stage 2 allows for 2 000 MW to be shed.