The Energy Advice Line has joined calls for energy companies to drop their prices after the cost of gas fell to its lowest level in more than a decade.
Julian Morgan, managing director of the price comparison, switching and advice service for domestic and business energy users, backed calls by consumer groups for energy companies to be more generous with their price cuts.
"Wholesale prices are at an historic low, yet suppliers have waited until recently - the end of winter - to make very modest cuts to household gas prices," Mr Morgan said.
"These companies can afford to make more significant cuts, and it should have happened sooner, not as we enter a period when most people are, or already have, turned their heating off.
"Energy companies talk about rebuilding trust with consumers but they need to do more than reduce prices by a meagre amount very late in the day if they are to win them back."
Figures released by price reporting agency ICIS showed that wholesale gas prices in the first quarter of 2016 were down by one third on the same period last year - the lowest since data was first collected in 2005.
ICIS analysts said falling prices were due to oversupply in all markets, and suggested prices could drop further, as wholesale gas contracts for delivery in future years were even lower.
Consumer groups have called for companies to make further cuts to their standard tariffs following only modest reductions in gas prices earlier this year.
The Big Six have offered customers gas price cuts of just 5% and no change to electricity prices, despite energy markets plummeting to historic lows.
"Energy companies are not doing the right thing, as they are refusing the pass on reasonable price reductions in line with falling wholesale prices," Mr Morgan said. "It is really important that consumers vote with their feet about this.
"Now more than ever it is crucial for consumers to stay informed about what is happening in the market and to demand a better deal from their suppliers.
"If supplier refuse to offer competitive prices then consumers need to switch to avoid paying more than they need to. With help from a reputable independent service like Energy Advice Line this can be quick and easy and most importantly completely free."
Energy Advice Line is one of the UK's leading price comparison and switching services for business and domestic energy customers. It is also an advocate for energy market reform and has campaigned for a better deal for energy users, including calling for a ban on cold calling and changes to regulations to make it easier for all consumers to switch suppliers.
The service is completely independent and free. Consumers can quickly and simply search the market for the best available energy deals from an extensive panel of small and large energy suppliers. The service also offers a free advice line for business energy customers.
For further information visit energyadviceline.org.uk