Low-cost airline Ryanair will be in the High Court this morning to challenge SIPTU's plan for strike action at Aer Rianta airports on Thursday.
The action is over plans to break up Aer Rianta's airports at Dublin, Shanon and Cork into separate companies.
The strike will be the day after St Patrick's Day when tens of thousands of visitors will be in Ireland for the celebrations and also coincides with a public transport work-stoppage.
St Patrick's week is also a time thousands of Irish people travel to Britain for the Cheltenham racing festival.
Ryanair says SIPTU has closed Dublin Airport three times in recent months and the latest action is a "kick in the teeth to visitors and Irish consumers alike". The company says disruption will be caused to over 50,000 passengers and it could take five days to restore services to full operational capacity.
Bus Éireann issued a statement today saying the public transport strike was not due to any dispute between the company and unions.
It said all services for the day are unlikely to operate and claimed the work-stoppage is a "breach of all agreed industrial relations procedures".
SIPTU's national industrial secretary, Mr Michael Halpenny, says the union have deferred industrial action several times to allow talks with the Minister for Transport, Mr Brennan, over his proposed break-up of the airport operator Aer Rianta.
Mr Halpenny said Mr Brennan has continued to progress his plans despite promising the union greater consultation and access to financial information.
"The Minister also promised progress on the issue of Shannon's future and indicated that any proposals for Shannon Airport would be as good, if not better than the current situation. Unfortunately none of this has come to pass," Mr Halpenny recently said.