GMB said about 350 of its members employed by Metsa Wood at Boston, Widnes and Grangemouth had rejected the current wage position and were seeking authority to ballot for industrial action to secure a better offer.
Dave Hulse, GMB national officer, said the union has worked hard with the company through difficult times in the past couple of years but said the door will remain open for a pay deal.
He said a notice for the ballot would be given in due course.
A spokesperson for Metsä Wood UK said the company does not comment publicly about its internal procedures.
