Staff at mining manufacturing business Fenner Dunlop have voted to go on strike for the first time in decades in a row over bonuses.
In a ballot by union GMB, more than 87 per cent of workers backed industrial action.
The affected staff number about 80 and although they now have a mandate to walk out, officials are still hopeful an agreement can be reached.
GMB full-time officer Dave Oglesby said the present bonus structure was unclear and needed fixing.
He said: "I believe there's some work being done with the bonus scheme and the other issues that were raised.
"However, we've had nothing put back to us formally or been given the opportunity to ballot the members on other proposals.
"Nothing will happen yet, until we've had it ratified by our regional committee, and we will see if there's any resolution on the matter."
The vote on action was triggered when staff rejected a 2.25 per cent pay rise.
The wage offer itself was not the main sticking point. However, union members had other concerns and felt action was needed.
In addition to the bonus scheme, there are also concerns about redundancy pay if any staff have to be laid off.
Workers at the factory in Marfleet Avenue, east Hull, must now take action within 28 days.
It means any strike is likely to happen before Christmas.
Mr Oglesby said: "It's been decades since we've got to this position but unfortunately we've got no option.
"Hopefully we will reach a resolution in the next week or so.
"The workforce is sensible, pragmatic and loyal – we don't want to be the ones to upset things. We're here because of the employers."
It is not yet clear how long industrial action will last if it is taken. That will be decided by members at a later date.
Mr Oglesby said: "It will be strike action. Whether it's all-out or daily or shift-based will be decided at a later date.
"We've got a clear mandate for industrial action. It will be affecting about 80 people."
Fenner Dunlop's management was not available for comment. Speaking last month when the GMB announced the ballot, HR manager Diane Quigley said staff had not had a chance to vote on their pay offer first.
The rise was calculated by looking at inflation figures and Ms Quigley believed it was fair.
She said: "The union has declined to put our offer to the members.
"We encourage them to have an internal ballot because at this point there's been no official vote on the offer that's on the table.
"Particularly since inflation has declined, it was a good offer at the time and it looks even more generous at this point."
The bonus scheme is being redeveloped and GMB is involved in discussions around it, she said.
The factory's parent business Fenner posted a £37.2m drop in profits in its annual results to August.
It blamed a weak pound and tough trading conditions in the US and Australia.
Revenues were down four per cent to £729.4m and pre-tax profits fell from £66.4m to £29.2m, the results showed.
At the time, chief executive officer Nicholas Hobson said results at both Fenner's advanced engineered products (AEP) and engineered conveyor solutions (ECS) divisions were "encouraging".
The Marfleet site is part of the ECS arm.
• Follow us on Facebook and Twitter
