ABOUT 20 buses belonging to Buscor went up in flames while parked at a depot in Daantjie near Nelspruit early yesterday morning.
The damage is estimated at about R50million.
A security guard at the depot told police that he heard a 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 said he tried to extinguish the fire using a portable fire extinguisher but his attempt to douse the flames failed.
He subsequently called the police and fire department.
KaNyamazane police spokesperson Inspector Andries Shikwambane said no one had yet been arrested for the apparent arson attack.
"We are investigating a case of malicious damage to property because we are talking about movable assets here," Shikwambane said.
"The damage has been estimated at about R50million."
Shikwambane said the police would investigate the possibility that the attack could be related to an ongoing wage dispute at the company.
Buscor spokesperson John Ngombe announced that there was a R50000 reward for anyone who providing 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," Ngombe said.
No injuries were reported.
Meanwhile, commuters from various settlements were left stranded when the buses failed to arrive yesterday.
Lillian Gazide, a commuter 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 in the area said they had been woken up by sirens and red flashes from fire department vehicles after midnight.