A spokeswoman for Betandwin.com told the UK's Observer newspaper that the company was in talks with the club about a deal, believed to be worth around £12million a year.
However, the Spanish press has reported that the talks have broken off because Barcelona was unable to meet Betandwin.com's deadline for agreement.
The club has never allowed its shirts to be sponsored before, and groups inside the club are fighting for and against the deal according to brandrepublic.com
The Betandwin.com spokeswoman told The Observer that it was unlikely the deal would be completed in time for the start of the next season.
Betandwin.com has more than two million users, covers more than 50 sports and is available in 20 different languages.
It recently grabbed the headlines after it secured exclusive international media rights to the German Bundesliga.
If it were to pay Barcelona £12million a year, the deal would top the reported £50million five-year deal recently agreed between Samsung and English Premier League champions Chelsea.
