Electric Ireland says that an issue which has led to some customers in the North having their power interrupted due to a fault with keypad top-ups may not be resolved until the middle of the week.
The company said an error had occurred which had capped some meters at a £10 (€11.70) credit limit.
The company said it had identified approximately 4,500 keypad customers who are affected and around 100 who have lost power.
A statement said: “Electric Ireland sincerely apologises to the approximately 100 customers who lost electricity supply as a result of an ongoing technical issue with some keypad meters.
“Many of these customers have had power restored.
“We are continuing to work closely with the network operator to reconnect those off supply, and are prioritising vulnerable customers.
“Of its 74,000 customers in Northern Ireland, Electric Ireland has identified 4,500 keypad meter customers who are potentially impacted by this issue.
“These customers topped up between August 30 from 00.00 hrs to August 31 at 13.23 hrs.
“We have contacted the vast majority of them over the weekend via text message.”
The company said that customers with a balance on their meter will remain connected until that balance has been used.
The statement added: “All customers who are currently on supply will remain connected until the end of the Friendly Credit period at 11am tomorrow morning.
“We have started to contact customers by text to let them know the actions that need to be taken, to return their meter to normal.
“Currently we anticipate this issue should be resolved for most customers by the middle of the week.”
Customers without power have been asked to contact Electric Ireland on Monday to Friday between 0830 and 1900 on 0800 313 4926.
Outside of these hours they are asked to contact NIE Networks on 03457 643 643.
The company added: “Customers should not top up their meter unless instructed to do so, as doing so may delay restoration of their service.
“We apologise that this technical error has inconvenienced our customers and assure them we are working to return normal service to all as soon as possible.”
Electric Ireland is the third-largest supplier in Northern Ireland.
