Storm force winds and heavy rains are expected to cross the country over the next two days.
Met Éireann has issued a weather alert with winds of between 100 and 130km/h expected tomorrow night and Monday morning.
The weather is being caused by the tail-end of Hurricane Katia, which is currently crossing the Atlantic.
Extremely high waves are expected on southwest, west and north coasts with wave heights of between six and ten metres possible.
Irish Ferries has cancelled a number of its Swift sailings between Dublin and Holyhead because of forecasts for the Irish Sea.
The Met Office in Britain has warned people to be aware of disruption to travel and the possibility of damage to trees and structures.
Katia is the second major hurricane of the 2011 Atlantic hurricane season and was rated as a category four hurricane on the Saffir-Simpson hurricane scale at its peak.
The scale rates hurricanes from one to five, with five being the strongest.