Eircom systems are returning to normal this morning.
Engineers have been working through the night to rectify yesterday's problem affecting certain landlines, mobile phones and ISDN lines on the eircom network.
Fianna Fáil said it is essential the cause of the fault is identified, to prevent a similar event happening again.
The party's communications spokesman Michael Moynihan wants Minister Alex White to request a full report.
"I would sincerely hope that he is going after this and he is properly briefed and properly reported," he said.
"I would also ask the commissioner for communications to take a very hands-on approach because this is very important for the fabric of society and we need to make sure that every arm of the State is pulling together with the companies to make sure the service is back up and running in an efficient manner, and in a manner that will not cause outages again."