Johannesburg - A Rea Vaya bus driver was attacked in Dobsonville, Soweto, on Tuesday, operator Litsamaiso said.
The man was reporting for duty when other drivers allegedly attacked him, the company's spokesman Babu Maharaj said.
He could not provide further details.
Litsamaiso manages the operations of the Rea Vaya's buses along with Piotrans.
Maharaj said Piotrans employees were on strike, but Litsamaiso workers could not work because of the sensitivity of the matter.
The companies both operated from the same depot.
He said there no busses were running as the company was waiting for the union to report back on whether they would accept a draft agreement tabled on Sunday.
Police spokesman Warrant Officer Kay Makhubela could not confirm the incident.
Rea Vaya drivers went on strike indefinitely on Monday, leaving commuters in Johannesburg stranded.
Drivers wanted labour brokers to be banned, the code of conduct be reviewed, senior staff members to be able to choose their shifts, and the union to be introduced during the induction of new workers. - Sapa