AFFCO has been ordered to reinstate a worker the Employment Relations Authority says was unfairly treated by the company.
AFFCO has also been told to pay Dennis Harris for being unjustifiably dismissed from its Moerewa site.
The company must reimburse three months' pay, and pay him $7500 for humiliation and loss of dignity.
AFFCO said Mr Harris had written the word "scab" six times inside the locker of another worker and damaged the locker.
But the authority said AFFCO's investigation into him was procedurally unfair, with significant defects.
AFFCO formed a view which it could not be dissuaded from, and there was no proper and substantive basis for Mr Harris' dismissal.
The entire investigation process was contaminated by systemic errors, the authority said.