The Commission for Energy Regulation has approved a reduction gas prices by 9.8 per cent and the average price of electricity by 0.2 per cent.
Small- and medium-sized enterprises will see electricity price reductions of 0.4 per cent and 5.5 per cent respectively.
Minister for Energy Eamon Ryan welcomed the announcement and said 2009 had been a good year for electricity and gas consumers.
He said it was clear the policy of greater competition in the Irish electricity market was yielding results for the consumer.
They can now reduce their electricity bills by up to 25 per cent and their gas bills by 22 per cent, he said.
"These are major savings at a time when money is tight for many people. The savings business can expect will protect jobs in this country."
"Our electricity and gas bills are largely dependent on price of fossil fuels in the international market. We remain far too dependent on imported fossil fuels. Promoting this combination of competition and renewable energy will help reduce our energy costs into the future.
"If we retain this dangerous dependence we will always be at the mercy of the international market. Our energy security and competitiveness will be best served by the switch to renewable energy," the Minister said.
A12 per cent reduction in gas prices and 10 per cent reduction in electricity prices was announced following an extraordinary review of energy prices in April of this year.
Bord Gáis and Airtricity announced that they would undercut the regulated electricity tariff by 10-14 per cent following their entry into the domestic supply market.
Mr Ryan said electricity consumers could therefore feasibly have a reduction of up to 25 per cent on their bills, depending on their supplier.