Bus services in the region could face severe disruption if Stagecoach workers vote for industrial action over pay.
The ballot is under way and covers company depots across Scotland including Dumfries and Stranraer.
Drivers, engineering staff, administrative workers and cleaners are taking part in the vote.
If members of the Unite union, who want a 4.8 per cent pay rise, back the call for industrial action, strikes could take place later next month and into late January.
And that could add to the disruption of public transport with some ScotRail train services being targeted for strike action each Sunday in a dispute involving RMT union members.
Bus workers claim the Stagecoach Group is proposing a below inflation pay offer of around two per cent.
Unite has demanded the company meet its “fair” pay claim of the Retail Price Index inflation figure of 3.8 per cent plus one per cent.
Dougie Maguire, the union’s regional co-ordinator, said: “Stagecoach’s stance has been nothing short of shocking, and it has infuriated the workforce who have continued to work diligently throughout the Covid pandemic.
“The Stagecoach Group is extremely profitable. It also directly benefits from millions of pounds of public funds every year through various Scottish Government schemes, not to mention benefitting from the UK Government’s furlough scheme for the last 18 months.”
He added: “If Stagecoach do not come to their senses then many of the nation’s major bus routes will grind to a halt if our members vote for industrial action.
“Remote local communities and showcase events such as the COP26 climate change conference will be severely disrupted. “This will be solely down to the group’s point blank refusal to make our members a fair pay offer.
“The solution is simple – give our members the pay rise they deserve or face widespread industrial disruption.”
Mr Maguire said Stagecoach’s latest accounts reveal that the Group made a profit of £58.4m, and it has over £875m of available in reserves.
In March, the firm announced further plans for 46 new fully electric buses across Scotland for which the Scottish Government is providing £9m of the funding under an ultra-low emission bus scheme.
A stagecoach spokesman said: “Discussions with Unite are continuing. We are committed to offering good packages for our people that reflect the local economic conditions, the varying costs of running services and the level of passenger journeys at a time when public transport is being financially supported by the Scottish Government.”