Barcelona coach Ernesto Valverde has dubbed as "strange" the decision to hold the Copa Libertadores final between Boca Juniors and River Plate in Madrid.

The derby match between Argentina's two great rival clubs had to be postponed last weekend after Boca's team bus was attacked by River fans on its way to the Estadio Monumental.

It had been suggested the fixture could be cancelled but Conmebol, the governing body of South American football, has instead opted to stage it in Madrid on December 9.

"It's strange," Valverde said on Saturday. "It's like if the Champions League final was played in Rio de Janeiro or in Buenos Aires."

Both sets of supporters will be given an equal allocation for the moved match, despite the first leg, which finished 2-2, being played only in front of Boca fans inside La Bombonera.

River also complained that Argentinian fans will be denied the chance to watch an historic game in their own country.

"It is something that has attracted a lot of attention and I know that there can always be exceptions but the truth is that this has caught us all by surprise," Valverde added.

"I guess we have to agree to it, it is up to Conmebol and the clubs. The fact it will be played here in Spain means there will be a great show for everyone but it still seems strange all things considered."

Earlier River announced they were refusing to play the game in Madrid while Boca are planniong to appeal the switch to Spain.