The organisation stated that the government should end "punitive" pricing against prepayment meter users, as the average user of the system pays £215 more than a Direct Debit online customer.
"Energy companies raise more than £320 million from prepayment users, around a million of whom are fuel poor. No wonder the industry was happy to sign up to the deal," Mr Asher said.
"The government is letting energy companies off lightly by allowing them to charge fuel poor prepayment users more and is letting millions of vulnerable consumers down badly."
energywatch's comments on the new system have come after the body welcomed Ofgem's decision to introduce new complaints handling standards for energy suppliers in the UK.
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