Mental health and intellectual disability services provider Pact says it will appeal an Employment Relations Authority finding that it misled negotiators and breached the collective agreement in the 2011 bargaining round.
The action was brought by the Service and Food Workers Union and the Public Service Association.
Pact was fined $10,000, split between the applicants and the authority.
Costs were reserved, with the parties invited to reach agreement.
In her February 28 determination, authority member Christine Hickey found Pact's failure to disclose it intended to backdate a pay rise to non-union employees misled the applicants, and was ''deliberate, serious and sustained''.
''The information was deliberately withheld; its effect was serious for the applicants in that it diminished their standing in their members' eyes and prevented them from negotiating a similarly backdated pay increase.''
Ms Hickey also found Pact breached a clause of the collective employment agreement by passing on the 2% pay rise to non-union members through a process that was not entirely separate from the collective bargaining process. Pact had about 363 staff, of whom 213 were covered by the collective agreement.
Pact corporate services director Paul Chamberlain said when contacted he did not accept Pact had acted unlawfully, and was preparing an appeal to the Employment Court.
The Service and Food Workers Union welcomed the ERA finding in a press release.
