The ESB's customer complaints arbitrator, Mr Denis Henderson, last year received 226 complaints, a 4 per cent increase on the previous year.
Ex-gratia payments or account credits paid to customers in respect of 53 resolved complaints totalled £19,608 (€24,897), a 33 per cent increase on the previous year.
According to Mr Henderson's annual report, which is to be published today, 193 of the complaints were resolved by his office or by the ESB. Most of the complaints, 74 per cent, were about networking issues including quality of supply, metering, supply connections and quality of work.
Customers with complaints can call Mr Henderson's office on 1850 321 325.