Rea Vaya bus drivers are on strike, the City of Johannesburg said on Thursday.
"The City of Johannesburg informs residents and passengers that there is a disruption of Rea Vaya services due to labour action by bus drivers for services that are operated by Pioneer Transport [Piotrans]," said spokesman Benny Makgoga.
"Piotrans management is addressing the situation. Passengers are advised to use alternative transport and Rea Vaya will be able to provide feedback at appropriate times."
It also affected the T3 from Thokoza Park to Library Gardens via Auckland Park, C2 Indingilza to UJ Soweto, C4 to Cresta, C5 to Florida North as well as feeder routes.
The F6 Lea Glen to Bosmont, F7 Fleurhof/Amalgam to Bosmont, F8 Westbury to Greymont, F9 Mapetla to Thokoza Park, F10 Lakeview to Pimville, F11 Yeoville to Library Gardens and F12 Parktown to Library Gardens were fully operational and were not affected by the strike.
Piotrans was not immediately available for comment.