Electric Ireland is to increase residential electricity and gas prices again from next month.
The company said residential electricity bills will increase by 26.7%, while residential gas bills will go up by 37.5%.
The change will take effect from October 1st.
This will be the utility's third price increase this year, following similar price rises in August and May.
It says the latest change is due to "unprecedented increases in international energy market prices and their impact on wholesale gas prices".
The increases will add around to €37.20 per month on to the average residential electricity bill, and €42.99 a month to a residential gas bill.
Pat Fenlon, executive director of Electric Ireland, said: "This continues to be a very challenging time for customers, and an unprecedented time in the energy industry with increases to wholesale gas prices in excess of 700% over the last 12 months and 200% since June 2022 alone.
"It is with considerable reluctance that we are increasing electricity and gas prices again for our customers, which is necessary given the continuing increases in wholesale energy prices, particularly gas."
The move will impact around 1.1 million electricity customers and 150,000 gas customers.
Daragh Cassidy from bonkers.ie said these increase are not sustainable.
"To say these are unprecedented times is an understatement.
"Price increases of this frequency and this magnitude are clearly unsustainable.
"During the last energy crisis in the ‘70s, the price of oil increased by around 400% on wholesale markets.
"We now have gas up by over 1,000%. That shows you the scale of the crisis we’re looking at."
He added: "We're heading into winter with gas and electricity prices at absolutely astronomical levels - and it could get even worse.
"The average gas and electricity bill is now around €4,000. That's close to the UK price cap of stg£3,549.
"The Government needs to decide now how it plans to help households over the coming months.
"To truly tackle the costs of spiralling energy prices, action will need to be taken at an EU level.
"Next week's proposed emergency energy summit is welcome news, as are talks about an intervention in the electricity market and a redesign to bring down prices."