Spain's secretary of sport has called for "sanctions" should the Spanish national anthem be whistled when it is played before Saturday's Copa del Rey final between Barcelona and Athletic Bilbao.
Basque and Catalan fans inside the Camp Nou on Saturday evening are widely expected to interrupt the playing of the Spanish anthem, as happened previously when Barca and Athletic met in the 2009 and 2012 deciders, when then king Juan Carlos was also whistled by supporters from both teams.
The Spanish authorities are currently keeping a close eye on fan behaviour inside stadiums, amid a crackdown on ultras groups following the death of a Deportivo La Coruna supporter before a game at Atletico Madrid last November.
A wide range of chants, including some directed at Real Madrid galactico Cristiano Ronaldo and Barcelona talisman Lionel Messi, have since been highlighted as unacceptable by the Spanish government's State Commission Against Violence, Racism, Xenophobia and Intolerance in Sport.
Secretary of State for sport Miguel Cardenal, an Athletic fan and member of the ruling conservative Partido Popular, said in AS that whistling the national anthem would cause offence to some people, and was therefore something which should be punished.
"If there remains intolerance in football grounds, it should not be strange to us that there could be sanctions imposed for a grave offence against the symbols of the state," Cardenal said. "It would be strange if there was not a punishment. There are people who could be offended. There is no reason to whistle a symbol of the state, it is a senseless thing to do."
Cardenal also called for political leaders in Bilbao and Barcelona to urge for respect for the anthem, with Spain's new king Felipe II also expected to be in attendance at the Camp Nou.
Barcelona's new mayor elect Ada Colau, an anti-poverty activist who surprisingly beat current Catalan nationalist party mayor Xavier Trias in last weekend's elections, said individuals had the right to express their opinion once they did so peacefully.
"In democracy, the freedom of expression is essential, as long as it is done peacefully," said Colau, whose husband Adria Alemany works for Barca's club foundation, in Sport. "They would do well to ask themselves the reason for the protests and boos."
Spain coach Vicente del Bosque also entered the debate, saying in AS that the national anthem should be respected by all fans at the final.
"What should be done is not whistle, because everyone wants a sporting final," Del Bosque said. "The anthem is a sign of identity for our country, and should be respected. In other countries nobody attacks or stamps on the flag, and the anthem is now whistled."