ESB Networks are working to restore power to thousands of premises around the country.
Wintry weather conditions and winds associated with Storm Bella caused the outages.
ESB Networks are reporting that there is a major fault in the Castlerea and Elphin area of Roscommon.
It's believed that power will be restored to the 942 households in County Roscommon that are affected by the outage by this afternoon.
ESB Ireland have apologised for the fault and are working to restore power as quickly as possible.