The company says Gardaí are investigating an individual based in the capital.
Ticketmaster is urging locals looking to attend concerts, matches or other events to be extra vigilant for fraudulent sellers.
The company says Gardaí are investigating an individual based in Dublin.
Ticketmaster says some people have already lost what its called "large sums" of money to this individual, who is claiming to represent it.
It says this fake seller is promising advance tickets or last minute tickets for collection from the venue on the day of the event.
These tickets don't exist.
Ticketmaster is working alongside Gardaí to boost its security and verification methods for upcoming events.
It's also urging anyone who has been a victim of this crime to get in touch with Gardaí immediately.
The company's statement is co-signed by partners including Croke Park, Landsdowne Road, the FAI, IRFU, MCD and the company that organises Electric Picnic.

New Appeals System For Asylum Seekers Comes Into Effect
Bord Bia Review Published In Light Of Controversy Surrounding Brazilian Beef Importation
KCC Report Reveals North Vs South Divide In Kildare
Kildare TD Highlights Difficulties Faced By Wheelchair Users In Curragh School
"A Fall Every Week" : Mayor Of Naas Calls For Alterations To Kilcullen Road
Local TD Accepts Data Centres Are A "Particular Issue" In Ireland
Kildare Dog Shortlisted For Bravest Pet Award
Kildare Senior Football Team vs Kerry