Paramedic service ER24 estimate around 100 people may have been injured in the collision, which occurred between the towns of Hennenman and Kroonstad in Free State province.

However  a spokesman for Netcare911, another emergency services group, tweeted: "Four people have been declared dead... with approximately 40 injured."

Witnesses claim part of the train burst into flames after it was hit by a truck, according to local media.

Video of the crash shows one of the train carriages on fire while passengers can be seen with their luggage waiting by the side of the track.

Passenger Seipati Moletsane told local media the truck could not brake and hit the first and second carriage.

The train, operated by Shosholoza Meyl, is believed to have been travelling from Port Elizabeth to Johannesburg.