Energy suppliers are being warned not to hike the direct debits of customers using less gas and electric - after complaints from households that their monthly payments are rising despite using less energy or being in considerable credit.

The government is writing to all domestic energy companies warning them to not 'over-estimate' charges and to ensure computer and payment systems are reacting to changes in people's behaviour.

Gas and electric prices rose by more than 25% at the start of October and are expected to rocket again in January and April - a move which has automatically made hundreds of thousands of households more energy conscious going into winter.

Sales of electric blankets, candles, slow cookers and other energy efficient appliances are reportedly up as people attempt to use less gas and electric to keep their usage low and bills down while social media is awash with stories of people who have continued to avoid using their heating thanks in part to a relatively mild autumn.

Homes are also currently receiving more than £65 in extra help each month - which will last until next March - under the energy support scheme which has given every property with a domestic energy contract an additional £400 to help cover rising bills.

Yet despite this, say ministers, there have been growing numbers of reports from customers who complain they are being asked to pay more and more each month in direct debit payments despite some deficit in their usage.

As a result, business secretary Grant Shapps is now writing to all providers asking them to make sure monthly bills are reflecting exactly what customers are using.

The letter reads: "It is critical that consumers are able to manage their bills effectively and direct debit can be an efficient way for families to smooth their energy costs over the year. However, I was disturbed to read media reports that some consumers are saying their direct debits are going up when they are making huge efforts to reduce their usage to save money at a time when household incomes are squeezed.

"It is in all our interests that when consumers take sensible steps to reduce their own bills, such as reducing their boiler flow temperature or making their homes more energy efficient, that they are able to see an impact in their bills."

The government is also going to be turning to energy regulator Ofgem, it says, for advice in ensuring energy companies are only charging households for an amount of energy which is an accurate reflection of what they are actually using over the course of the year.

The letter adds: "I am very keen that all suppliers find a way to make their systems more responsive to these positive changes in consumer behaviour and have asked Ofgem to report to me on how this can be achieved."

Co-founder of energy comparison site, Choosewisely Tara Flynn believes the energy payment system does need further attention.

She explained: "Energy providers must review how they’re working out customers’ direct debits and let them know how to claim credit back if they wish to. Your money should never be held at ransom - if you’ve built up enough credit, you should be able to request your money back anytime.

"I empathise with the reasons why energy firms charge more than customers are using each month, to spread the cost of heating during the winter, but with so many customers choosing not to turn the heating on or dramatically changing their habits to reduce their bills, there should be a simple way to request or automatically receive a refund if credit reaches a certain amount.

"£200 credit sitting in a customer’s energy account this December could make all the difference to a family’s Christmas."