Unite called on the owners of a Carling brewery in Burton-on-Trent today not to slash workers' pay and conditions following a cut in beer duty.
The union urged brewers Molson Coors not to attack the wages of 184 brewery technicians by up to £9,000 a year.
Unite said the company had been pushing for a reduction in beer duty, which was included in Wednesday's Budget.
Chancellor George Osborne scrapped a planned 3p rise in beer duty, reducing it by 1p.
More than 300 workers at Burton town hall voted unanimously on Thursday night for Unite to hold a strike ballot.Another meeting will be held at the town hall on Monday night at 6.30pm for shift workers that missed the vote.
Unite regional officer Rick Coyle said: "Molson Coors had made great play for the need to reduce beer duty to help its profitability.
"Now that has happened management should reconsider its punitive plans to cut the pay and conditions of staff."
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