Dublin Bus drivers are warning of potential industrial action over a ban on them listening to the radio while on duty.
The new rule came into force yesterday and the National Bus and Railworker's Union (NBRU) says its members will be balloted on Thursday.
The union says one of the main points of concern is health and safety in the Port Tunnel, where all drivers must have a radio turned on so that emergency services can interrupt the transmission in case of emergency.
General Secretary Dermot O'Leary says his members do not want to strike, but drivers should not be punished.
He says a number of drivers have already been 'booked' - having had disciplinary measures recorded against them.
“Whilst it will be for the Dublin Bus branch of our union to ultimately decide on the type of industrial action which they would undertake should Dublin Bus up the ante, our members are determined that they will not be forced to stop buses and discommode a supportive travelling public as a result of this ludicrous ban on transistor radios," Mr O'Leary added.