Over 100 Plymouth First bus drivers have voted for industrial action over management scrapping the staff bus.
Workers in the RMT union voted for action that may include a strike and an overtime ban.
The staff bus drops workers at its Chelson Meadow depot at 6.02am, Monday to Saturday.
Bosses claim the bus is under-used and uneconomical, but the workers’ RMT union say it is the “axing of essential staff transport”.
The service was set up before the firm was privatised.