Dublin Airport car park prices must be reduced ahead of the busy summer period - as people pay over the odds due to capacity issues.
Fine Gael Senator Emer Currie wants customers to be protected from spiralling costs.
Dublin Airport Authority says the price increase is due to the time of year, high demand, and decrease in supply.
A long-term car park at the airport was sold, meaning the loss of 6,000 spaces.
The authority says it operates a "dynamic" car-park pricing system.
Media relations officer, Graeme McQueen, says the pricing model helps control demand.