The Irish Taxi Drivers Federation has said it condemns anyone over-charging customers at Dublin Airport.
It follows a clampdown in which seven drivers were arrested yesterday, the majority for not using the shortest route into Dublin.
The offence can lead to prosecution and a fine of up to €2,500.
President of the Irish Taxi Drivers Federation, Joe Heron has said those who commit an offence have a high chance of loosing their permit to work.
"I was very very bothered that there would be such over-charging in that manner by going a longer route," he said.
"Anybody that works with the airport and commits an offence of that nature, the chances are high they will lose their permit for work in the airport."