A Spanish judge on Friday overturned a controversial ban on Barcelona fans flying Catalan flags at Sunday's Copa del Rey final against Sevilla in Madrid.

The Madrid authorities had told Barcelona on Wednesday that the Estelada independence flags could not be flown at the Vicente Calderon stadium, the home of Atletico Madrid because they contravened a 2007 law.

That legislation allowed for a ban on flags and symbols that are deemed to "incite violence" or "show contempt for participants in a sporting event".

But the judge on Friday ruled that "in no case had it been proven" that the exhibition of the flags could "incite violence, racism, xenophobia or any other form of discrimination that is an affront to human dignity".

Barcelona said they welcomed the judicial decision to allow the display of Estelada flags.

"The club celebrates that the judge's decision will allow the free expression of legal symbols and banners by its members and supporters," the Spanish champions said in a statement.

"At the same time, FC Barcelona expresses its concern about the reoccurrence of situations like the one on Wednesday, and which are an affront to the freedom of expression, and do nothing to benefit what has always been a celebration of football and sport.

"The club reiterates its commitment to the defence of the freedom of expression among its members and supporters."