Some 27 people were killed in a bus crash outside Piet Retief on Tuesday, Mpumalanga police said.

Superintendent Abie Khoabane said the Bhekezakho bus driver lost control of the vehicle and it plunged into a river about 45 kilometres from Piet Retief.

"Twenty seven people including the bus driver were killed. The bus was coming from Piet Retief, travelling to Houtkop farm when the accident happened," said Khoabane.

It was also not yet known how many people were on board the bus at the time of the crash.

The injured were taken to hospitals, said Khoabane.

Sapa