Approximately 27,000 electricity meters need to be replaced due to faults resulting in overcharging customers.
ESB Networks says around 17,000 meters may be currently affected by the fault and they plan to test these meters.
The failure causes the meter to over-record and then stop working altogether.
Those overcharged will be refunded.
A spokesman said: “ESB Networks advises all customers that they do not have to take any action with their meters.
“ESB Networks will contact all affected customers and test the meters.
“ESB Networks apologises to all affected customers that this problem has arisen with one of our metering suppliers.”