ESB Networks is advising households and businesses that they are working to resolve an issue which caused some smart meter readings to be processed incorrectly last week.
It has apologised for the "confusion and concern" this may have caused and said they are reviewing their processes to ensure this does not happen again.
It follows reports of numerous electricity customers highlighting significant price hikes on their meters in recent days, with some as high as €5,000 for one day.
Many customers took to social media to reveal the "impossible" and "wild" costs on their smart meters on 6 and 7 March.
One Bord Gáis customer described how on 5 March his meter read 4.18 kW use for the day at a cost of €1.83. While the next day the cost rose to €738.
Another person said their meter showed they had used 7000kW in one day at a cost of €2,500.
Customers also said they had been assured by their suppliers that it is a "known issue" that is being fixed this week and that no action is required from them.
ESB Networks has since explained that last Friday a planned software upgrade to one of their internal systems caused some customers' meter readings to be processed incorrectly, resulting in high and incorrect usage on ESB Networks online accounts and on those of suppliers.
In a statement it said it is an internal software issue and is not related to the integrity of smart meters or the recorded energy use.
"We are in the process of identifying and resolving the issue in our systems and will systematically correct all affected data."
It said customers do not need to do anything at this stage and will automatically adjust metering data to reflect actual usage.
It is estimated that there are around two million smart meters installed across Ireland.
