Eircom says all its phone lines are back working in Dublin.
There was an 'intermittent' service on mobile, land and ISDN lines since ten this morning.
Dublin Fire Brigade had warned that the outage could make it difficult to make emergency calls.
Childline also advised children trying to use its service that they may be experiencing problems.
Those affected can't call customer care centres, so are being advised to report the fault online.
