Bord Gais is increasing the average gas bill by 39% and electricity bill by 27%.
The changes come into effect on April 15th.
In a statement, the company says the move is in response to high global wholesale costs and market volatility, which is expected to continue.
Price comparison website Bonkers says the increase will add around €350 a year to the average household’s annual gas bill and €340 to the average annual electricity bill.
Bord Gáis also say it's putting in additional supports for customers who will have difficulties managing their bills.
An energy support fund will be established and there will be tailored advice to help customers.
Next month, a €200 energy credit, including VAT will be paid to households next month to help with the soaring rises in bills.
In a statement, Bord Gáis Managing Director Dave Kirwan said,
"We know that today’s announcement is not welcome news. As part of Centrica plc, and with decades of local experience, we will navigate through these unprecedented times with our customers.
"However, there have been continued increases in wholesale energy costs over the past two years, particularly in the past 12 months.
"This, together with the expectation that costs will remain both high and volatile for some time, means we are forced to increase our prices.
"We know that each customer’s circumstances are different, and we are determined to help those who need it most.
"That is why we are announcing an energy support fund of €1.25 million in addition to the services we already have in place.”
Meanwhile, in response to the price hike, Bonkers said,
"Today’s news from Bord Gáis is sadly unsurprising given the huge increase in the price of gas that we’ve seen on wholesale markets in recent months.
"However, the size and scale of the increase is unprecedented.
"It’s the first price hike announcement from any energy supplier this year.
"Last year there were over 35. And more suppliers are certain to follow. The outlook is bleak for energy customers.
The increase will add around €350 a year to the average household’s annual gas bill and €340 to the average annual electricity bill.
"But this comes on the back of price hikes that have added around €540 to customers’ gas and electricity bills since the autumn of 2020.
"Bord Gáis raised electricity prices three times last year and gas prices twice."
