Spanish champions Barcelona filed a complaint with the country's football federation (RFEF) criticising perceived refereeing inconsistencies on Saturday.
Triggered by the club's anger at a controversially disallowed goal in the 4-0 Copa del Rey defeat by Atletico Madrid on Thursday, Barca wrote to the RFEF and Spain's refereeing committee (CTA), demanding more transparency.
Barca said in a statement their letter expresses "deep concern over repeated refereeing decisions it considers detrimental (to the club) and lacking a consistent standard".
The Catalan giants highlighted "the existence of disparate decisions responding to actions of identical nature", which they say creates a "double standard", AFP reported.
Barca said there has been a "pattern of flagrant refereeing errors throughout the season", many of which have set them back, which "directly affects the integrity of the competition and fuels growing mistrust".
They also called for greater transparency in the use of VAR, with a clearer criteria for when referees are called to review actions, and requested the full publication of all VAR audio.
Several other clubs have complained about refereeing in Spain this season, while Real Madrid have regularly criticised referees through their television channel over the past two seasons.
In February 2025 Real Madrid published an open letter claiming Spanish refereeing was "rigged" and "completely discredited" after they fell to a surprise defeat at Espanyol.
Barcelona are currently being investigated by Spanish authorities in a sports corruption case after paying former CTA vice-president Jose Maria Enriquez Negreira seven million euros ($8.3 million) over several years. The club deny any wrongdoing.
