The Dublin Airport Authority has warned that operations at Dublin, Cork and Shannon airports may be affected by industrial action next Monday, in a row over pensions.
The DAA has been served with notice of potential industrial action by SIPTU and Mandate.
The High Court granted the DAA permission to seek an injunction against SIPTU on Friday to prevent any work stoppages.
Earlier, The Dublin Airport Authority began High Court proceedings against the trade union SIPTU aimed at stopping industrial action planned for next Monday.
Lawyers for DAA told the court the planned action would close Dublin, Shannon and Cork airports if it goes ahead.
The authority said any industrial action is a breach of current agreements and it plans to bring an application for an injunction this Friday.
The High Court has given permission to serve SIPTU with notice of the action.
The court was told there were issues between SIPTU, the DAA and certain airlines over a significant pension deficit.
The issue is currently being dealt with by the Labour Relations Commission.
Senior Counsel Brian O’Moore said two groups of employees critical to operations - fire and police, and the search unit - were parties to agreements with a no-strike clause.
Under the agreements with these workers, disputes should be dealt with through labour relations mechanisms, he said.
Mr O’Moore said SIPTU had served notice of industrial action to begin on Monday in the form of staggered two-hour stoppages.
The union will be served with notice of the proceedings today and the injunction application will be heard at the High Court on Friday.