Undercover gardai will be out in force tomorrow targeting ticket touts ahead of the All-Ireland Final.
A crackdown on scalpers selling above face value tickets is a gardai priority for the showpiece event at Croke Park between Dublin and Kerry.
Touts who have a history of operating illegally could face huge fines and a maximum six-month prison term if convicted.
A Garda source told the Herald: "Ticket touting is a big priority for gardai and there will be officers deployed specifically to target and tackle touts.
"This will be an undercover approach and gardai will be briefed on who the main people are selling tickets above face value ahead of the match.''
Garda are also warning match-goers to only buy tickets from licensed sources.
"There will be a significant Garda presence as expected. Gardai will target individuals suspected of selling tickets, over face value, without license.
"When purchasing tickets for concerts and other events, Gardai advice to the public is to purchase tickets from authorised sources only."
It comes as gardai investigate an on-the-run convicted Dublin fraudster suspected of defrauding €420 from a mother who believed she was buying tickets for the All-Ireland clash.
Gardai believe Wesley Brennan (32) met with the woman in a Fitzgibbon Street cafe under a promise of collecting the tickets in a GAA shop around the corner on Tuesday. However, he and the money disappeared.
The victim has spent more than two hours this week helping gardai track down the criminal from her home in Leixlip, Co Kildare.
She said Gardai are "closing in" on the main suspect in the case. The woman added that he made a fatal error in his scam that will "almost certainly" lead to his arrest.
Meanwhile, Brennan, from Tallaght, is on the run from a Northern Ireland prison since January last year when he was given home leave while on remand for allegedly creating false online adverts offering tickets for the 2017 All-Ireland Final.
Brennan was previously jailed in 2015 in Dublin after being convicted of stealing a woman's car on a first date after the pair met on a dating site.
He asked her could he drive for a while, but when in the driver's seat he drove off and later sold the car to a scrap yard in Ashbourne, Co Meath. Brennan was jailed for 18 months.
Another Dublin woman claimed a friend had been scammed out of €1,400 for sports tickets after meeting Brennan on the same website.