A total of 360,000 customers have had power cut by Hurricane Ophelia according to the ESB which has warned that it could take up to 10 days before electricity power is restored.
Bernadine Maloney, Head of Corporate Affairs at the ESB, said the midlands and all parts of the country have been hit.
"We have 360,000 businesses and customers out at the moment. With this number of customers out - it is unprecedented it is going to be a number of days, 10 days, before 5% of customers get their power back.
She said people who are vulnerable or who have medical vulnerability need to make provisions if the ESB be cannot get the power back straight away.
She said crews have begun to work on assessing the damage.
"Every part of Ireland is affected by this," she said.
"This is going to be a long hard slog. Trees will need to be cut down. This is pole by pole. There are over 3,000 faults on the system and each one of those takes a huge amount of time individually (to repair)," she said
She said smart technology would allow power to be restored in the short term if the network has not been damaged. She warned of intermitment cuts as repair works is carried out in the coming days.
She said the ESB is set to call in crews from Northern Ireland and other parts of Britain to help carry out repairs.
She also warned people that power cables that have fallen are live and dangerous so they should not approach when they venture out after the storm dies down.
The company says the priority will be taking calls relating to emergency & dangerous situations on ESB Networks on 1850 372 999