Golden Arrow Bus Services staff around the country will go on strike later this week after wage negotiations deadlocked, the company said in a statement on Monday.
The MyCiTi bus service in Cape Town would be suspended for the same reason.
Golden Arrow said unions that were party to the South African Road Passenger Bargaining Council had given notice of their intention to go on strike from Wednesday.
The company said it was not in a position to remedy the situation, as the council comprised employer associations and unions representing the entire local bus industry.
"As a result of the strike action, Golden Arrow will institute a company-wide lock-out in order to ensure the safety of our passengers and staff for the duration of the strike."
GOLDEN ARROW 'HOPEFUL'
All services will be suspended from Wednesday until further notice.
"This decision is not one which is taken lightly and we remain ever cognisant of the integral role that our services play in the lives of our passengers."
Golden Arrow said it remained hopeful that all parties would return to the bargaining table.
Weekly and monthly clip cards that are valid when the strike commences will be extended when the service resumes, it said.
In Cape Town, there would be no MyCiTi trunk or feeder services available as from Wednesday morning, for as long as the strike and lock-out continued, said transport mayoral committee member Brett Herron.
"We regret the inconvenience caused and the additional pressure it places on commuters to make alternative travel arrangements," he said on Monday.
"The strike will have a serious knock-on effect on all public transport and road-based traffic as nearly 71 000 commuters make use of the MyCiTi service on any given weekday."
The city would engage with Metrorail and the South African National Taxi Council to see how they could assist in accommodating commuters.
Herron said they expected a significant increase in the number of vehicles on the roads, as commuters would either opt for minibus taxis or use their own private vehicles to get to work and back.
"I therefore want to call on private businesses in Cape Town to consider implementing flexible working hours or remote working arrangements for employees where possible and practical for the duration of the strike action."
Car-pooling was another option.