EDF Energy has put up prices by 3.9% today, meaning customers paying by cash and cheque will see their average bill increase by £47 from £1,190 a year to £1,237.
The move comes just days after British Gas cut its fuel bills by 3.2%, after raising them by a massive 9.2% on 23 November 2013 after the government stepped into to quell soaring prices across the industry by cutting some environmental levies.
Npower, Scottish Power and SSE all increased their prices at the end of last year but are also due to part-reverse the price rises. However, they are yet to announce firm details of their reductions.
Claire Osborne, energy expert at uSwitch.com, urged them to help their customers by announcing their plans soon.
"While EDF Energy, E.ON (which put its prices up by 3.7% in early December) and British Gas customers now know where they stand, the same cannot be said for customers of the other Big Six suppliers," she said.
"The lack of meaningful conversation regarding price cuts will not be going down well with consumers as it seems to demonstrate a complete lack of understanding of the pressure they are under."
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She added: "We would urge suppliers to tell their customers now about the price cuts they will be making and to ensure that any reductions are backdated so that customers will feel the benefit throughout winter. It does not seem fair that some consumers are left with higher winter bills simply because their supplier delayed passing on the benefit of government changes to the levies on bills."
Lack of transparency
Meanwhile, a senior partner at Ofgem has admitted that the energy regulator is unable to test claims made by the Labour party yesterday that customers have been overcharged for electricity by £150 for the past three years.
Ofgem's Ian Marlee blamed a lack of transparency for the lack of investigation.
Tom Greatrex MP, Labour's shadow energy minister, crisiticed Ofgem following the admission.
"It is just not good enough for Ofgem to say it doesn't know whether consumers are being overcharged – it's the regulator's job to know. There is now clear evidence that suggests all the big energy companies have been buying electricity at above the market price," he said.
"Today's revelations show why we need a tough new regulator and reforms to the energy market to stop these firms from overcharging. The only way to get proper transparency in the energy market is to stop energy companies from selling power to themselves and make them do all their trades in a proper open market."
Ofgem is at least trying to make life a bit easier for consumers. Since 2 January it has banned suppliers from offering confusing and complex tariffs in a bid to make it easier for consumer to get a better deal.
Indeed, sesearch from comparison website Gocompare.com has revealed one in five (19%) Brits find the choice of energy suppliers so bewildering that they stay with their existing suppliers instead of shopping around for a cheaper deal.
As a result of the rule change, suppliers can no longer offer tiered tariffs where consumers are initially charged a higher rate, which falls the more energy they use. Once a consumer has decided how they want to pay for energy, they now have four tariffs to choose from for gas and four for electricity from each supplier.
However, Jeremy Cryer, Gocompare's energy spokesperson, said the move doesn't go far enough.
"Restricting the number of discounts that can be applied to two - dual fuel and online account management - makes things simpler but it doesn't help those who aren't internet savvy, for example, many elderly people, as they as they can't benefit from energy suppliers' online deals and will continue to pay much more for their gas and electricity than they need to," he said.