Spain's Minister of Economy, Trade and Enterprise, Carlos Cuerpo, said Friday that concerns over banking market concentration caused by BBVA's hostile takeover bid for its smaller rival, Sabadell , will ease when the European Union's banking union becomes a reality.

"Once the relevant market is the EU market, then in terms of competition we will be able to alleviate our concerns about this increase in scale of banks and relevant players at the European level. We have to keep working to achieve that scale," he said in an interview with CNBC.

Cuerpo said Thursday that Spain's government opposed BBVA's hostile bid for Sabadell because it was concerned that the Spanish market would be dominated by a few large banks.

(Reporting by Inti Landauro and Matteo Allievi; editing by Mark Potter; Spanish editing by Javi West Larrañaga)