The UK’s Competition and Markets Authority (CMA) says price comparison websites help consumers “make informed choices and save money”, but it also flags concerns about the way they operate.

Comparison websites “could be more transparent” and the benefits could be improved if suppliers were to make more information available, the watchdog says in a report.

“Certain practices and contractual arrangements” could limit healthy competition, and the way comparison sites are regulated may also be a concern.

“Our work so far suggests that digital tools such as price comparison websites generally work well for consumers, who really value the service they provide,” CMA Acting CEO Andrea Coscelli said.

“Among the areas we wish to consider further are what can be done to increase confidence among consumers and how to improve competition, regulation and transparency in the sector.

“We are now seeking further views on these issues as part of our wide-ranging market study.”

The CMA report shows 84% of people seeking car insurance in the past year used a comparison site. Only 11% of recent users believe sites cover all suppliers.

Comparison sites for general insurance products have made less impact in Australia because the major insurers refuse to take part. Companies such as IAG and Suncorp believe such websites encourage a focus on price at the expense of policy suitability.

The CMA’s final report will be published by September 28.