Ofgem must keep an eye on energy suppliers to see that they treat their customers fairly, a consumer group has said.
Audrey Gallacher, head of energy at Consumer Focus, called on the industry regulator to "keep the pressure on" so that companies are not tempted to over-charge.
The comments come after an interim management statement from Centrica, the owner of British Gas, suggested that energy bills would rise later this year due to volatile gas and electric markets.
It suggested that nuclear issues in Japan and the political unrest in the Middle East have pushed up wholesale prices, which may be passed on to consumers.
Ms Gallacher responded: "Consumers did not get the full benefit of sustained low wholesale prices and have less confidence in the energy market than almost any other.
"They will sadly not be surprised to see suppliers quick to bump up prices to protect their inflated margins."
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