Bord Gáis Energy has said that due to a technical issue with its banking service, some customers' direct debit payments were taken twice today.
It is believed that most of the company's customers who were affected by the error have been communicated with and the issue has been resolved for most of them.
Bord Gáis Energy apologised for the error and said it was investigating how it happened.
In a statement on its website the company said that due to an error with the banking system, some of its direct debit customers have experienced a double direct debit taken from their bank account today.
"We apologise for this error and are investigating the root cause with AIB to avoid any recurrence of this issue in the future," the company said.
"In some cases, this error has already been reversed. We're working closely with the bank to ensure the error is reversed for all customers as soon as possible," it said.
"Again, we apologise for the inconvenience and will be updating customers through multiple channels throughout the day," it added.
A statement from AIB said the bank is reversing the duplications of payments.
The bank said that many customers will receive the reversals today, and for others this should be completed by tomorrow, 27 April.
"We apologise to anyone who has been impacted and if any AIB customers have questions they can contact us on 0818 724 724," the bank added.
