The Meat Workers Union has rejected an offer by AFFCO to reinstate all locked out and striking workers.
The company locked out 900 unionised employees two months ago following a impasse over a new collective agreement.
About 500 union members are on strike in response.
AFFCO says it told the union it would reinstate all workers at a rate of 300 staff a week as long as the union stopped its strike action and continued with mediation.
The union says it rejected that because it would take five weeks to get all employees back to work and that it is urgently seeking an injunction on the lockout, which would ensure all workers get their jobs back immediately.
Mediation talks between the two continue on Tuesday.
A full court hearing on the legality of the lockout has been set down for 16 May.