People wanting to switch to another energy supplier are being deterred from doing so by some of the largest firms.
Customers trying to get a quote from companies including British Gas, E.ON, ScottishPower, EDF and OVO Energy have allegedly been advised to stick to their current supplier.
Earlier this month, Liz Truss announced that the mandated Ofgem price cap of £3,549 would be reduced to £2,500.
Companies appear unable to offer a cheaper deal to people who want to change their current energy supplier.
An Ofgem spokesperson told ELN: “We expect licensed energy suppliers to take on new customers when approached by them and to ensure their connections are appropriately metered.
“Where this is not being done, we will engage with suppliers to ensure compliance with this requirement.”
An E.ON spokesman told ELN: “With energy prices at a record high, it is recommended that customers stay with their existing supplier.
“However, customers can sign up to receive an alert as soon as we are in a position to offer competitive fixed price tariffs for new customers or can call us to discuss their tariff.”
ELN has approached British Gas, EDF, ScottishPower and OVO Energy for comment.