The PSNI has warned concert goers to "be on the look-out" for ticket fraud linked to the One Love Manchester concert.
The fraud alert came as the PSNI said the National Fraud Intelligence Bureau were aware of "reports and posts in both the news and on social media" about tickets for Sunday night's concert were being fraudulently offered for sale.
Tickets for the concert, organised in the wake of the Manchester Arena concert bomb which left 22 dead - including an eight year-old girl - sold out within minutes of going on sale on Thursday.
Police have warned that tickets bought from any unofficial sources, usually for overinflated prices, are likely to be counterfeit and anyone in possession of one will be refused entry to the concert.
The event at Old Trafford Cricket Ground, will be headlined by Ariana Grande. The US singer had just finished performing at the Manchester Arena on Monday May 22 when a suicide bomb was detonated.
Other performers lined up to take part include Justin Bieber, Katy Perry, Coldplay, Take That and Miley Cyrus.
Meanwhile, it was also revealed toay that more than 10,000 people applied for free tickets to the concert despite not attending the pop star's gig last week.
Ticketmaster had set aside tickets for the 14,200 people who were at the Manchester Arena concert that was targeted.
However, more than 25,000 people applied.
A spokeswoman for Ticketmaster said: "Sadly, over 10,000 unscrupulous applications have been made."
Major secondary ticketing sites such as Seatwave, Get Me In, Viagogo and Stubhub have all pledged to not allow the reselling of tickets on their websites, while eBay said it would immediately remove any listings attempting to profit unfairly from the terror attack.