AFFCO is launching what it calls a serious misconduct action against meatworkers at the company's Rangiuru plant who took last Monday off work following Waitangi Day.
Workers who took a Monday-ised Waitangi holiday are being called to a meeting with management to discuss their actions.
A letter sent to Checkpoint with John Campbell said workers might be in breach of their employment agreement, and their absence could amount to an unlawful strike.
AFFCO has refused to discuss the letter's contents with RNZ.
Meanwhile, in a case affecting a different group of workers, the Employment Court has ruled that locked-out workers at AFFCO's Wairoa plant should be able to return to work on their normal shifts and the company should recognise their seniority.
In November, the court ruled AFFCO had unlawfully locked out workers and breached good faith.
The Meatworkers Union said the company had responded by putting all workers on the night shift, regardless of their employment agreement and seniority provisions.
The union hoped that as a result of the latest ruling the workers would be back at work within two weeks.
A group of workers, speaking from the union's ofice, told Checkpoint, they were incredibly proud of the win.
But one, Teena Edwards, said she was not confident the ruling would be honoured. "They're going to try and kick us around, bugger us around, for a little while. That's my feelings - I'm hoping I'm so wrong."
In a statement this afternoon, AFFCO said the judgment was subject to an application before the Court of Appeal.
It maintained it had not locked out the workers, saying they have had opportunities to work at the plant since it opened this season.
The long-running dispute, affecting 164 workers, arose when a collective agreement with the meat company expired in December 2013 and the company locked out staff who would not return on individual contracts.