"All our drivers did not turn up for work this morning, there are no buses running," said Putco spokesperson Romeo More.
The South African Transport and Allied Workers' Union (Satawu) announced the strike on Thursday and said it was a result of a wage negotiations deadlock.
Errol Braithwaite, spokesperson for the Gautrain company Bombela Concession, said none of the Gautrain buses were operating.
"We are waiting to hear what comes out of the negotiations at the bargaining council," Braithwaite said.
Joburg Metrobus spokesperson Esther Dreyer said municipal buses were operating across the city.
Workers were demanding an 18% wage increase and the employers had offered only 2.5%, said Satawu spokesperson Vincent Masoga.
6.5% offer on the table
However, Barry Gie, chief executive of the Commuter Bus Employers Organisation, which is part of the negotiations at the bargaining council, said employers had put a 6.5% offer on the table.
He said the unions' claim of a 2.5% offer was "misleading".
"Negotiations are a two-way process; both parties need to compromise in order to resolve the dispute … the unions are misleading the public."
Workers were also demanding a minimum wage of R6 000 a month across the industry, a R1 000 housing allowance and an increase in medical aid contributions, said Gie. – Sapa