The drinks giant – whose brands include Johnnie Walker, Captain Morgan, Bell’s and Baileys – could see employees strike in the run-up to Christmas over plans to remove staff from a final salary pension scheme to save £30m a year, union GMB Scotland said.
Both GMB Scotland and Unite members have voted in favour of action, a move described by Diageo as "clearly disappointing" and "premature" because discussions between the company and unions are still ongoing.
“The company and employees are in a consultative process and have not yet moved into consultation on the alternative proposal,” Diageo’s statement said.
“It is also far from the positive industrial relations of past decades that the company has had with its employees and which has helped build the reputation our supply business has today.
“If and when strike action is taken, the company will focus on ensuring that our business continues as usual as far as possible.”
GMB Scotland, which has 1,200 members working with Diageo in Scotland, said 63% of members voted for strike action and 69.7% voted for action short of strikes.
“Our members have sent a strong message to Diageo that the company needs to think again if it wants to avoid damaging strikes across Scotland,” GMB Scotland organiser Louise Gilmour said.
"Diageo is happy to significantly increase executive pay in the wake of billions of pounds of profit but it won't protect the pensions of the workforce who have contributed massively towards the success of the business."
She added the move was "another example of obscene disparity between executive pay and the ordinary worker".
Unite members across Diageo’s UK sites voted 82% in favour of industrial action short of a strike, and 77% in favour of strike action.
The union’s regional officer Pat McIlvogue said: “We are proud of our members who have sent a clear message to Diageo that they must keep their pensions promises.
“No one takes industrial action lightly – especially with Christmas coming up – but Diageo is behaving like Scrooge."
According to Unite, Diageo sites in Scotland, Northern Ireland and Runcorn, Cheshire, could be affected by the dispute.