MADRID, June 11 (Reuters) - The Spanish stock market supervisor said on Tuesday it had admitted BBVA's application for authorising its 12.28 billion euro ($13.19 billion) hostile takeover bid for Sabadell, a potential tie-up that Madrid opposes.

The admission of the application by National Securities Market Commission (CNMV) is part of its regulatory process for approving deals.

"The admission for processing of the application does not imply any type of pronouncement on the decision concerning the authorisation of the takeover bid," the supervisor said in a statement.

The deal also requires approval from the European Central Bank and Spanish antitrust watchdog CNMC.

Last month, BBVA's all-share offer was rejected by Sabadell, prompting Spain's second-largest bank to go hostile in its latest attempt to buy the country's fourth-largest lender after a failed attempt in 2020.

The combined group would overtake Caixabank as Spain's biggest bank by domestic assets, in the latest consolidation drive in the country's banking sector.

BBVA will be seeking to persuade regulators of the merits of the deal, which the bank said could take six months or eight months, before formally going to shareholders.

Under the Spanish legislation, the Spanish government cannot stop a takeover process but has the final word on authorising a merger.

BBVA expects the deal to complete by mid-2025.

($1 = 0.9308 euros) (Reporting by Jesús Aguado, editing by Inti Landauro and Shinjini Ganguli)