Business secretary Greg Clark has vowed to take "decisive" action on energy prices, but admitted any intervention may not take place until after the election.
Speaking to MPs, Clark said the government will respond "very shortly" to a report from the Competition and Markets Authority (CMA) on the energy market, adding he was "disappointed" by the failure of suppliers to react.
Addressing the Business, Energy and Industrial Strategy committee this morning, Clark said the CMA had identified consumer detriment "of an average of £1.4bn a year in recent years".
"When you are presented with that degree of consumer detriment we have a duty to act, and we will do so in our response to that report," he said.
"It's clear that the market isn't working for those customers on the default tariffs. The CMA has established that. It's been my very clear view...and when I say that we have a duty to act, you will see that action. It will be decisive and it will address this completely unacceptable detriment that ordinary working people have been suffering."
However, Clark stopped short of promising movement by the government ahead of Theresa May's planned June election.
"When you have an election that is called, there is a number of things that are in the final stages of preparation that you need to reflect on whether they can be finalised in time. That is something, to be candid with the committee, that we are reviewing," he said.
Former minister John Penrose has been pushing in parliament for a cap on energy price increases for consumers, but Clark declined to be drawn on whether this was a course the government will follow.
A government paper had been expected to appear as soon as this month, but the business secretary denied consumers were losing out while ministers continue to mull a long-awaited response to the CMA report.
BEIS committee chair Iain Wright told Clark bills were continuing to rise in the meantime.
"There's no delay. The response that we will make will be muscular and will be strong and will apply to all of the companies that are disadvantaging consumers in this way," Clark said.
Last week EDF became the latest supplier to hike its dual fuel tariff, pushing up prices by £78.