Eircom says there are between 3,000 and 5,000 customers without phone lines since last night's storm.
The worst affected areas are on the east coast, from Drogheda to Wexford, and in the south, around Cork and Limerick.
More than 400 field staff working over the weekend to restore services as soon as possible.
Meanwhile, the ESB says it hopes to reconnect most of the 1,500 homes still without power this evening.
