Employees of a Scottish whisky maker are set to strike next month in a move a union has warned could affect supplies to shops and bars over the festive period.

Around 800 members of GMB Scotland and Unite working for Chivas Brothers will walk out of work in the weeks running up to Christmas after a formal ballot over a pay dispute.

GMB Scotland has warned the planned action could disrupt orders to retailers, hotels and public houses over the holidays.

The action comes after Chivas Brothers, the producer of global brands including Chivas Regal, Glenlivet, Ballantine’s and Royal Salute, allegedly refused to revise a previous pay rise offer of 6.4%.

The union announced results of the strike ballot on Tuesday, with 89% supporting action after an earlier consultative vote also revealed high levels of support for strikes.

Meanwhile, Unite said 91% of its members also supported staging walkouts after previously rejecting the 6.4% pay offer by 97%.

David Hume, GMB Scotland organiser, said the vote demonstrated staff’s determination to secure a better offer at a time Chivas and French parent company Pernod Ricard are reporting “unprecedented sales” of its products.

He said: “After a year when household bills rose again and again, our members have made clear they will not accept a pay rise that is, in reality, a pay cut.

“It would be unacceptable at any time but the company’s owners celebrating some of the highest-ever sales only adds insult to injury.

“Huge profits are built on the shoulders of our members and they deserve to be paid fairly and receive an offer that recognises the value of their work.”

Unite general secretary Sharon Graham said: “Strike action at Chivas Brothers is inevitable unless the current pay offer is improved. Chivas made an eye-watering profit last year, and it can easily afford to offer our members a significantly better offer.

“Unite will back our Chivas Brothers members all the way in the fight for better jobs, pay and conditions.”

Chivas is believed to employ around 1,600 workers in Scotland, including at the Kilmalid bottling hall, in Dumbarton, Strathclyde Grain Distillery, Glenlivet Distillery and maturation sites and distilleries in Speyside, Clydebank and Ayrshire.

A spokesperson for Chivas Brothers said: “We’re disappointed that a small majority of our employees covered by a bargaining agreement have voted for strike action.

“As a business, we firmly believe that our pay proposal strikes the right balance in ensuring salaries remain highly competitive in the context of a normalising business and economic environment, as further indicated by this month’s drop in inflation.

“Our current offer, combined with last year’s increase, would see salaries increase above the CPI and CPIH inflation averages seen over our last two financial years.

“We remain committed to our proposal and open to continued dialogue to see this matter reach a resolution.

“Should industrial action go ahead, we are prepared to put in place the necessary measures to ensure our continued business operations, minimising any impact to our customers around the world.

“As most of of our end-of-year orders have already shipped, we are confident this ballot result will have no impact on the festive season.”