Hundreds of Teesside steel workers are being balloted on industrial action over unpaid bonuses.
Union bosses say Corus has gone back on a pledge to pay quarterly bonuses to more than 300 workers at the company's tubes mill in Hartlepool.
The firm says the bonuses have not been paid out because of outstanding negotiations with the unions.
But the Community Union has accused the firm of trying to water down a deal guaranteeing quarterly bonuses in 2009.
The ballot comes as the future of 2,000 jobs at the company's sister plant in Redcar remain in doubt because of a shortage of orders.
'Drive down wages'
Roy Rickhuss, Community Union national officer, said: "We have repeatedly stated we are willing to sit down and talk, but we will not allow Corus to put a gun to our head and negotiate away our members' terms and conditions under duress.
"Corus management are using the recession as an excuse to drive down wages and turn back the clock."
In a statement, the company said: "Corus has written to employees reaffirming that bonuses cannot be paid for the quarter just ended in view of the fact that bonus agreements with the trade unions for 2009/10 have not been concluded.
"The company is hopeful that discussions with the trade unions can commence shortly and have confirmed to employees that any payments due under the new agreements will be paid to them at the next scheduled payment date."
The ballot, which could lead to strike action, is due to close on 9 November.