Catalan newspaper L’Esportiu first broke the story on Wednesday and it was followed up by Cadena Cope radio station.
A linesman who will not be named was told to favour Real Madrid in the upcoming Clasico slated for November.
Barcelona’s vice-president, Susana Monje, said: “I hope it does not prove to be true.We will possibly discuss at it a meeting of the board. All I can say at the moment is that if it is confirmed, it will be a dangerous story in terms of the prestige of La Liga.” The claims have not been substantiated.
Miguel Cardenal, Spain’s secretary of state for sport, said: “This is an extremely serious accusation and is extraordinarily alarming. This needs to be resolved as soon as possible. We cannot be talking about threats without knowing who is it. No one should be scared. It cannot be reasonable that in 2015 someone can fear reprisals for making an accusation like this.”