The Australian Competition and Consumer Commission is taking Trivago to the Federal Court, alleging the hotel booking comparison site made misleading hotel price representations in TV and online advertisements.

ACCC chairman Rod Sims said the watchdog was concerned websites such as Trivago gave the impression they were designed to benefit consumers when in fact listings were based "on which supplier pays them the most money".

A screenshot from a Trivago TV ad in December 2017.

"If you look at Trivago's advertisements it's got a lot to do with getting the best price, when in fact the hotel that comes up in the listings is the one that’s paid Trivago the most money," Mr Sims said.

"We would allege it’s all to do with Trivago making their site look more attractive to the suppliers. Not the consumers, the suppliers.