Power utility Eskom on Wednesday called on consumers to switch off geysers, pool pumps and all non-e.
Dubbed "Tsunami", "Bulldozer" and "The Caterpillar", Sithole was a well-known charismatic Durban evangelist who travelled around the province and amassed thousands of followers.
Spokesperson for NJ Sithole Ministries International Walter Ntsele said Sithole's death came as a shock.
Ntsele said Sithole was a long suffering diabetic patient.
He said his sugar levels spiked on Monday evening and the pastor was rushed to St Augustine's Hospital from his Umlazi N section home.
Sithole founded God's Army Evangelistic Ministries and established the network of Christian Fellowship Centre Churches.
"He will be greatly missed as he was recognised as the Moses of our time, a bold and courageous man," Ntsele said.