Multitalented artist Winnie Khumalo hopes her health will improve when she goes under the knife in J.
"No incidents have been reported so far," said deputy chief electorate officer Sy Mamabolo.
"There has been a steady flow of voters since stations opened in the morning."
Over 200,000 people were registered voters in the 25 wards. By-elections were held Johannesburg, Tshwane, Cape Town, Nelson Mandela Bay and Mangaung.
The Electoral Commission of SA (IEC) said Wednesday's by-elections were one of the largest mobilisation of voters outside the general elections.
Out of the 25 vacancies being contested, 12 were as a result of candidates being elected to the national and provincial legislatures after the May 7 general elections.
Mamabolo said the IEC expected the number of voters to increase when people returned from work.
"We expect more voters between 5pm and 8pm when people return from work. Stations will remain open until 9pm after which counting will commence," he said.