Workers at the Gaymer cider factory in Shepton Mallet, Somerset, are balloting for action over pay.
The ballot covers more than 100 Unite union members.
They accepted a 3 percent pay rise last year after three years of frozen pay.
Bosses then said this would be conditional on a pay freeze the following year.When workers rejected this, bosses took the 3 percent off the table.
The ballot closes on Friday of next week.