Wigan Council's fleet mechanics are balloting for strike action in a row over having to work later on Fridays as part of a number of rota changes.
Trade union Unite says the employees, who repair and maintain almost 300 vehicles used by the local authority, have been asked to accept "one compromise too many" as the council attempts to reduce its overtime bill.
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The sticking point in the dispute is over finishing times on Fridays, with the union deciding to hold the ballot after workers were told their request to be able to go home at 4.30pm rather than 5.30pm on the last day of the week was being refused.
The ballot which will decide whether industrial action is taken or not runs from December 5 until December 17.
The union says employees have "reluctantly" accepted a shift from a four-day working pattern to a five even though it will leave some staff up to £400 a month worse off as they will not be able to work as much overtime as previously.
However, it is unhappy that the one specific request made by the fleet mechanics has been turned down by the town hall.
Wigan Council, on the other hand, said it believed its offer was fair and said it had been listening closely to its staff.
Unite regional officer Tanya Sweeney said: “Our members have bent over backwards to help the council save money. Some will lose up to £400 a month in overtime pay but still they have acknowledged that the council is struggling financially and accepted its proposals.
“Instead of recognising the sacrifices our members have made, the council has decided to push things over the edge. Leaving one hour early on a Friday afternoon is not an unreasonable request considering the loss of earnings and schedule changes our members have agreed to.
“They have been asked to accept one compromise too many, which is why this ballot is going ahead. After all the goodwill shown by our membership and the disruptive consequences across the council that a stoppage to vehicle maintenance would bring, it has to be asked whether the council’s senseless intransigence on this matter is really worth it?”
Wigan Council said it intended to continue the conversation with the employees and union and hoped to avert industrial action.
Paul Barton, director for environment, said: "We have worked closely with our staff and union colleagues and have fully consulted with them on the proposed changes, most of which have been accepted.
“We have listened to the consultation feedback and have negotiated our proposals appropriately. We believe we have offered a very fair package which importantly meets the future operational needs of the service.
“We are still hopeful we can reach an amicable conclusion, without the need for any industrial action.”