Strike action at Diageo sites in Kilmarnock, Port Dundass and Shieldhall moved a step closer as a ballot of workers opened.
Last month, Diageo rejected the Scottish Government's alternative business plan to stave off the closure of its Kilmarnock and Port Dundas sites at a cost of 900 local jobs.
The ballot will start today and run until 30 October. Trade union Unite claims that Diageo is threatening to cut redundancy terms to the minimum if workers don't accept restructuring plans, which would see 400 jobs created at its Fife packaging plant.
"Our members are determined to fight to save their jobs and are not prepared to be thrown on the dole simply to further boost Diageo's already huge profits," said Jennie Formby, Unite national officer for the drink sector.
"They will show the strength of their anger when they vote on industrial action but we urge the company to avoid needless conflict by reopening dialogue with the workers and their unions on a fairer way forward on restructuring."
Diageo chief executive Paul Walsh has previously said that he is not prepared to put the other 4,000 jobs in Scotland at risk by keeping the either the Kilmarnock plant or the grain distillery in Port Dundas open.