Drivers from Piotrans, operating the Rea Vaya buses around Johannesburg, were on strike for a second day on Tuesday, the company said.

The drivers abandoned the buses on Monday without any explanation, said Piotrans GM Dumisani Mntambo.

"There has been no communication from the drivers or their union," he said.

"The company will start following the processes regarding company policies but there is no operation of the buses until further notice."

Spokesman for Rea Vaya, Benny Makgoga said he hoped the issues between Piotrans and the drivers would be resolved soon.

"We are hoping that there'll be some agreement reached but there are no guarantees," he said.

Commuters were urged to use alternative transport in the interim.