The ANC has retained all six wards contested in Wednesday's by-elections in the Eastern Cape, Free State, Mpumalanga and Northern Cape.
One ward in Peddie in the Eastern Cape was uncontested.
The ruling party's Sindile Toni won Ward 31 in the Buffalo City Metro which was also contested by the Democratic Alliance.
The Independent Electoral Commission said the ANC retained the ward, which includes Kayser's Beach, Fort Grey, Kidds Beach and Ncera Villages, with 65.74% of the 4358 votes cast.
Voter turnout was 46.41%.
DA Eastern Cape leader Atholl Trollip says his party had increased its support in the ward from 26.28% in the 2011 municipal election to 29.61% in the poll.
