The notion that Barcelona, home to around 1.6 million people, could become a second capital for Spain was touted by mayoral candidate Jaume Collboni on Monday.
Collboni, running for the city's top job with the Catalan wing of Spain's major opposition party the Socialists — a minor political force in the region — also proposed that the national senate be transferred to the coastal city.
The plans are part of a bid to bring Madrid and Catalonia closer together given growing independence aspirations in a region which is home to 7.5 million people. The Catalan government recently staged a symbolic vote on the issue of a split from Spain despite Madrid's conservative government blocking the poll in the courts.
The Socialists believe a more federal Spain with increased powers for the regions could be answer to Spain's seemingly intractable Catalan problem.
But Barcelona's current mayor Xavier Trias, with Catalonia's pro-independence CiU coalition, was quick to talk down Collboni's proposals.
"All these ideas don't make sense. Barcelona is the capital of Catalonia. It's one thing to work together and another thing to be a co-capital. What we need to do is compete with cities like Milan, Brussels and Paris," Trias was quoted as saying by Catalan newspaper La Vanguardia.
The head of Spain's centrist UPyD party Rosa Díez also laughed off the move to make Catalonia a new capital. "Have we all gone crazy or what?" she asked journalists on Tuesday.
Díez was dismissive of plans to move the senate as well, saying Spain should be fighting excessive spending and duplication of functions. The senate was "useless and obsolete", she said, adding it should be shut down rather than relocated.
Meanwhile, Madrid Mayor Ana Botella argued now was not the time for such a move.
"The capital of Spain is Madrid, according to our constitution, and therefore (changing it) would require a constitutional change in which I don't believe, and which doesn't come at the right time for our country," Botella said, according to Spain's Vox Pópuli newspaper.
However, the Madrid headquarters of the Socialists greeted the proposals more positively.
For the party's studies and programmes head Meritxell Batetit, it made sense that come institutions would be present "in different parts of the country".
The plans fell within a "federal concept, where not all institutions are concentrated in the same place but rather spread throughout the country in such a way that the State is present in different territories," Spain's Huffington Post quoted Batetit as saying.
The idea of conferring Barcelona second capital status is being seriously considered by Spain's ruling Popular Party, business news agency Bloomberg reported on Monday. A government spokesperson declined to comment on the issue, the agency said.