Wholesale prices have dropped in recent months
Energy company Npower is to cut domestic gas bills by 7% from 26 March, following price cuts by other suppliers.
The company has become the fourth of the "big six" energy suppliers to announce a reduction in prices.
Customers will see an average fall of £50 on their annual bill as a result of the change, the company said.
Wholesale gas prices have fallen over the last year, prompting the latest flurry of cuts in domestic bills.
"We always aim to offer competitive prices to our customers and we have lowered our gas prices although our profits halved in 2009," said Kevin Miles, chief executive of Npower Retail.
The company is also making changes to its discount structure for those customers who pay by direct debit.
For dual-fuel customers, the discount remains at £100 after 12 months using the payment system. But for gas-only customers, the discount rises from £20 to £50, and for electricity-only customers the discount doubles to £40.
The announcement came after British Gas dropped its gas prices by an average of 7% at the start of February.
This was followed by Scottish and Southern Energy, which will cut its standard household gas prices by an average 4% at the end of March.
On Monday, E.On said it would reduce its prices by 6% for domestic customers, also at the end of March.
Among the "big six" suppliers, only EDF Energy and Scottish Power have yet to make any announcement about gas prices.
Gas providers have come under pressure to cut bills after the prices they pay on the wholesale markets fell recently. However, some are unhappy with the similarity of pricing.
"The days of cut-throat price competition seem a distant memory. All suppliers now cut by almost identical margins within days of each other," said Audrey Gallacher, energy e-
xpert at watchdog Consumer Focus.
"There are no sprinters in this race, all we have are long distance trudgers desperate to stay in the safety of the pack.
"These are very different companies, with different buying strategies but the response is the same. All signs of competition are absent in this sector. We need to revive the market and a Competition Commission referral seems the best option."