Price comparison site uSwitch has defended its service after it was reported that consumers were not being shown the best deals.
The company said it was testing its website in line with regulator rules after a report said the cheapest prices were initially hidden in searches.
According to The Sun, consumers were shown deals from companies that had paid uSwitch for promotion, with the best deals only revealed when a box was ticked on the search page.
A uSwitch spokesman said: "We are continually testing our website to make sure we provide the most straightforward comparison journey.
"This test is in line with Ofgem's current proposals for the Confidence Code. Throughout the trial all customers have been able to easily see all energy deals available on the market with one click.
"Our mission is to help consumers save money on their bills and last year we saved them over £320 million on their energy bills alone."
Comparison sites are required comply with a set of rules introduced by Ofgem in 2014 to receive accreditation.
The regulator says the code insists its members follow key principles that provide reassurance to consumers about the "independence, transparency, accuracy and reliability of the service".