The haulage truck driver, carrying sugar cane used in ethanol production, had tried to overtake another truck from the same company near Checheche in Chipinge district when it rammed into the omnibus heading the opposition direction.
Police spokesman Assistant Commissioner Paul Nyathi said nine people were confirmed dead on the spot.
The crash heightened tensions between Greenfuel and locals, who accuse the company of grabbing their land and failing to improve local infrastructure.
Locals say the Tanganda – Checheche used by Greenfuel trucks used to be tarred, but it had since become a dirt road. Greenfuel trucks raise so much dust that other motorists cannot see ahead.-zimlive