Some hotels in Galway are reportedly charging more than €500 a night during the Races.
It has sparked calls for the industry to be regulated.
Dermot Jewell from the Consumer Association of Ireland said those in the sector need to be sent a clear message.
He said that hotels are in a “fortune position” in terms of VAT and government support of tourism.
“You’re ruining it for the majority by being entirely greedy and fleecing people that come to visit in what is a relatively small country,” he said.
He added that hotels should be aiming to offer good prices and value for money to punters visiting the city.