The Surrey-based company said sites such as Travelsupermarket have become recognised in the market as market leaders for best deals, but the “reality” is that consumers are unaware that car hire companies pay to be on the sites through pay-per-click deals.
Marketing director Gareth Robinson said the meta search sites are failing to search the entire web.
The comments came as Carrental.co.uk unveiled a new-look website this week.
“We have developed what we believe is the first genuine car hire comparator with extensive reach,” Robinson said. “It uses the latest technology to search up to 40 car hire sites for the best possible deals available at any one time.
“No major comparators have done this to date, meaning consumers may not be getting as good a deal as they thought.
Travelsupermarket states on its website that deals from 25 car hire providers are available on its search engine.
Travelsupermarket.com’s Chris Nixon said: “This statement is utter nonsense. It has been issued by this car hire comparison service as a cheap swipe to drive attention to its re-launch.
“We welcome the competition because providing the customer with choice is what travelsupermarket.com is all about. That is why we value highly the feedback from millions of our users which we use to make improvements to our service.
“This way we ensure we give customers the experience they want as well as providing a comprehensive access to the best deals and information, which is exactly what we do.”