Local 1 voted 77 per cent against Viterra’s offer, while Local 2 members voted 61 per cent against it, GSU information says.
A month prior, GSU members voted in favour of strike action if necessary.
By law, GSU or Viterra would have to give at least 72 hours of notice before a strike or lockout could occur.
The offer GSU members voted on during the Dec. 15 vote came from Viterra on Nov. 17.
GSU acknowledged the offer took steps in the right direction but lacked in multiple areas like pay improvements, earned days off, working from home and weekend booking pay.
More talks between the two sides are scheduled.
On its Facebook page, GSU announced it will meet with Viterra reps on Jan. 3 and 4 with the assistance of a federally appointed mediator.
The mediator’s role will be to help GSU and Viterra reach a solution. But it will still be up to the two parties to agree on it.
“While your bargaining committees express cautious optimism and remain committed to securing the best possible collective agreement, it is prudent to stay prepared for any circumstance,” the union said.