The public service union says ACC has breached employee contracts with its working-from-home rule change.

The PSA's taking the agency to the Employment Relations Authority. 

It says ACC gave the union only one hour's notice when it told staff four weeks ago they would have to come into work three days a week - up from two. 

PSA National Secretary Fleur Fitzsimons told Andrew Dickens that ACC promoted jobs with three working-from-home days.

She says workers who got the roles now feel deceived. 

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