ABOUT 20 buses belonging to Buscor were torched while parked at a depot in Daantjie near Nelspruit yesterday morning.
The damage caused is estimated at R50million.
A security guard at the depot told police he heard some noise shortly after midnight.
He said when he walked towards the parked buses, he suddenly saw flames coming from one of the parked buses.
He claimed he tried to extinguish the fire using a portable fire extinguisher.
He subsequently called the police and firefighters.
KaNyamazane police spokesperson Inspector Andries Shikwambane said no one had been arrested so far.
"We are investigating a case of malicious damage to property because we are talking about movable assets here.
"The damage has been estimated at about R50million," he said.
Shikwambane said police would investigate everything, including the possibility that the incident might have been related to the ongoing wage dispute that has been going on for quite a while.
Buscor spokesperson John Ngombe announced that there was a R50000 reward for anyone who could provide information that would result in the arrest and conviction of people responsible for the incident.
"This is a huge loss and we have decided to offer a R50000 reward to anyone who might help with information that will lead to the arrest and possible conviction of the suspect or suspects," Ngombe said yesterday.
No injuries were reported.
Meanwhile, commuters from various settlements were left stranded when buses failed to arrive yesterday.
A commuter, Lillian Gazide from Daantjie, said: "We have bought tickets and now some crazy people have burnt our buses.
"We were forced to ask for lifts to work but others had to return home."
Many people claimed they had been woken up by sirens and red flashes from fire department vehicles at midnight.