Ofgem has warned of the "inevitability of rising energy prices" and said the market "looks like it may well get tighter" as it urged suppliers to work to win back consumer trust.
The regulator's chief executive Andrew Wright said "rising pressure" on wholesale markets meant it was "more important than ever that consumers feel that they can trust the market".
He told the Ofgem conference 'Re-engaging consumers in the energy market': "It's important that, and I don't want to be a harbinger of doom... but potentially the inevitability of rising prices, that consumers feel confident that these rising prices are both fair and justified."
He called on suppliers to use Ofgem's reforms for a "simpler, clearer and fairer market" as a "golden opportunity to win back customer trust".
He said: "Consumers are frustrated and angry that the latest round of price rises have happened at a time when incomes are already being squeezed.
"Consumer confidence in the energy market is very low and suppliers must use our reforms to reach out to consumers and restore trust in the sector.
"Consumers who have never changed their energy supplier can save up to £200. Our reforms are already beginning to kick in as most suppliers are now offering just four tariffs for gas and four for electricity. This will make it far easier for consumers to pick out the best deal for them.
"Our reforms are the best chance for consumers to see immediate benefits through simpler tariffs, clearer information and much more consumer protection. The reforms give consumers the choice they value and the simplicity they need, but it is now for suppliers to get behind not just the letter of the reforms but the spirit as well.
"We will be watching suppliers' actions very closely and have already committed to report on the health of the market next year.
Ofgem has warned since 2009 that both prices and security of supply would come under pressure as Britain grapples to attract significant levels of investment to replace ageing plants and to meet tough environmental targets while becoming increasingly dependent on imported sources of gas.