The Service & Food Workers Union says a Supreme Court decision giving 50 cleaners the right to negotiate redundancy entitlements is a lesson for employers.
The workers from Massey University had been trying to negotiate a redundancy since 2010 when the cleaning contract was taken over by the company, OCS.
They were sacked and only reinstated only after accepting new conditions.
Their contracts excluded redundancy payments, but the Supreme Court says laws protecting workers affected by redundancy allow them to negotiate for non-monetary entitlements, such as the opportunity to retrain.
The union says OCS carried out widespread cuts quickly and without consultation. It hopes other companies will think twice before trying the same thing.