SIPTU members in Trinity College, Dublin have voted for strike action.
The union represents around 500 members of the non-academic staff.
The union's John King says the dispute is over management's failure to offer permanent contracts to staff:
"What we're seeing is that when staff are being recruited to replace staff who have left they are being recruited on precarious forms of fixed-term and non-permanent contracts of employment."
Mr King says they'll meet on Wednesday to discuss their next step.