Free MTV tickets on sale for £150 online
Ebay has said it is removing any tickets being sold on its site for a free outdoor concert in Belfast.
The BBC has seen tickets for the concert being sold on a number of online sites - some for more then £150.
Northern Ireland rock band Snow Patrol will headline the gig at the City Hall on 6 November to coincide with the MTV European Music Awards at the Odyssey Arena.
American RnB star Jason Derulo will also perform.
Belfast City Council has said it will investigate any complaints about the "illegal" sale of tickets.
Ebay said staff were "trawling the site" for such tickets, adding "we do not allow free tickets to be sold on Ebay".
Hundreds of people queued for hours at Belfast's Welcome Centre ahead of the release of 15,000 tickets at 08:00 BST on Sunday.
Tickets were also available by telephone and online, but they were all allocated within an hour.
On Monday, the BBC found a pair on sale on the internet for £310.
The seller informs perspective buyers: "These tickets were obtained free of charge and therefore you are bidding for my cold, damp camping time on the streets of Belfast."
Belfast City Council said each ticket had been allocated a number and "therefore may not be exchanged, given or sold to a third party".
"Profiting from the sale of free tickets is also a clear breach of the terms and conditions of obtaining a ticket and is illegal," the council added in a statement.
"The council will investigate any complaints regarding this - should they emerge."