Amicus is due to ballot its members on industrial action regarding what it says are Unipres’ plans to introduce Saturday working, without consultation.
The union says this comes as a result of a new practice of ‘banking’ working hours on Friday and making them up at the weekend.
But Unipres has rubbished Amicus’s claims.
Graham Baines, general manager - finance and administration at Unipres, said: "Employees have always been required to work a reasonable amount of overtime, a high proportion of which is on Saturdays. This has not changed. The plant will not close - only the appropriate number of employees will be stood-down in line with the requirements of the customer."
He also denied that workers will have to ‘payback’ hours on Saturday.
"This is incorrect," Baines said. "Workers will have to pay back a 'maximum' of six shifts. There is no mention that a stand-down shift is 7.8 hours whereas a stand-up shift is only 5.25 hours or that the first stand-down shift is ‘free’ and does not have to be worked back. There is also a one-off payment of £200 for the first stand-up shift."
Baines stressed that Unipres has been involved in an "extensive consultion" process with employee representives since July 2005.
"As part of this process we made a number of improvements and concessions to the system on the request of employees. We reached a position where the employee representatives and unions were able to recommended the deal to the workforce. The system was introduced in November 2005," Baines said.
Unipres has 770 employees of which 257 are Amicus members. The result of the strike ballot is due to be known on January 18.