Workers at a South Shields double-glazing company went on strike last Friday over pay.
The 12 workers at Walker Profiles Northeast took action over claims their bonuses were cut by almost a fifth last month.
The GMB union members are taking the firm to an employment tribunal later this month as they say the new bonus scheme will leave them about £75 worse off each week.
The disgruntled employees say they will down tools each Friday until the matter is resolved.
Worker Kevin Malley said, “This new scheme has put some of the workers on the breadline due to the fuel and energy bills hike.
“Many of us are now having to look for second jobs just to get by.”
GMB spokesperson Martin Gannon said, “With rising inflation, the employees cannot afford to take a pay cut and are highly dependent on their bonus.”