An Irish Rail spokesman said that Conor McGregor's father Tony should get a leap card to avoid excess change when paying for tickets.
“We’d recommend that Mr McGregor resolves the problem by purchasing a leap card," they told Independent.ie.
“If money is as tight as his trousers, he’ll save on his fare as well. You can save up to 31pc using a leap card."
On Sunday, Mr McGregor hit out at the Dart ticket machine - insisting that all the coins received in change don't fit in his designer suits.
In a bizarre social media rant, Tony McGregor said he received €17.30 in coins from a €20 note for a dart ticket from Lansdowne Road.
In his Instagram post - which has gone viral over the past 24 hours - Tony said there is no room in his Hugo Boss suit.
"I tendered a brand new €20 note into the automatic machine, looking for a single ticket to Dun Laoghaire," he said.
"They had the bloody cheek to give me back...and I'm gonna show you this coinage.
"€20 - €17.30 and a miserable little one-way ticket, they gave me all that coinage.
"I have no room to put those coins anywhere.
"I wear a slim-fit, hand-fitted, Hugo Boss suit," he added.