The clash between Athletic Bilbao and Barcelona is currently scheduled for May 25, just over two weeks before Spain's first game of the European Championship
The cup clash is currently pencilled in for May 25, a mere 16 days before Spain's opening Euro 2012 game against Italy.
With several of his side's key players set to be involved in the Vicente Calderon showpiece, Del Bosque has asked the governing body to move the fixture to May 16 to aid his preparation for Ukraine-Poland.
However, the RFEF is reportedly unwilling to change the date, as are the two clubs, who feel it would interfere with the travel arrangements.
Having crashed out of the Champions League and with La Liga slipping away, the Copa del Rey is Barcelona's last chance to add silverware to their Spanish Supercopa, Uefa Supercup and FIFA Club World Cup triumphs. Athletic, meanwhile, will compete in the Europa League final on May 9 against Atletico Madrid.