SSE has announced a 4.1% a cut in gas prices from 30 April 2015 that will save customers on standard tariffs £28 a year on average.
The company said the cut means its typical gas bill will be 7% lower than the same time last year.
SSE's current freeze on standard energy tariffs will be extended to at least 1 July 2016, making the 15-month dual fuel fix (that charges for the gas at the new lower rate) the longest-ever of its type in the market.
Steve Forbes, SSE's director of GB domestic, said: "Only SSE customers can bank on the fact that their standard energy prices won't increase under any circumstances before July 2016.
"Our prices are coming down, they're staying down and we want to work with government to bring them down further."
Drive down rising costs
SSE wants the government to take action "to drive down the other rising costs which make up more than half of the bill, including government-sponsored environmental and social policies and its smart meter roll-out costs", it said in a statement.
It added: "To protect customers, particularly the most vulnerable, SSE believes these policies should be funded through taxation and related to people's ability to pay."
Responding to the company's price reduction rather than its calls for action, Secretary of State for Energy and Climate Change Ed Davey said: "It's good news for households when energy suppliers cut their prices and they should pass savings on to their customers whenever they can.
"But even greater savings are available if people shop around and switch supplier - over £300 in some cases."
EDF is the last remaining member of the Big Six energy companies not to have announced a cut to its standard gas tariffs.
Npower is to cut gas prices by 5.1% from 16 February, Scottish Power by 4.8% from 20 February and British Gas 5% from 27 February. E.On has already cut its prices by 3.5% with the cut coming into effect immediately when it was announced on 13 January.
Independent supplier Ecotricity is to make a bigger cut than any of the Big Six at 6.1%, although it will not be introduced until 1 May.
Stephen Murray, energy expert at MoneySuperMarket, has welcomed the fall in gas prices but has repeatedly pointed out that they're merely "a drop in the ocean compared to the fact that wholesale prices have dropped by 20% in the last year".
He has also warned that the Big Six energy tariffs are generally around £200 higher than the cheapest available on the market.