MADRID, June 29 (Reuters) - Spain's CNMC competition watchdog on Tuesday approved the acquisition of Liberbank by Unicaja, though the merged lender will have to accept several concessions in its retail-banking arm in an area in western Spain, it said.

The new entity need not divest any of its businesses, a CNMC spokesperson said.

In December, Unicaja agreed to buy Liberbank for around 763 million euros ($908.20 million) to create Spain's fifth-biggest domestic bank with total assets of around 110 billion euros.

The merger, part of a banking industry consolidation in Spain and Europe, will reduce Spain's banks to 10 from 55 prior to the 2008 economic crisis.

The CNMC said the new entity would not command an effective monopoly in western area of Caceres, but cited some risk for customers in three postal codes in this province, such as higher fees for Liberbank clients.

To address this, Unicaja will offer its products for three years on the same terms as those in areas where it competes the most.

Liberbank and Unicaja declined to comment.

The deal, which is expected to close by the end of the second quarter or beginning of the third, also needs a green light from Spain's Economy Ministry.

Shareholders of both lenders gave their blessing in December to the transaction, which is underpinned by annual cost savings of 192 million euros.

The market value of the merged entity is worth close to 2.3 billion euros.

The combined entity would have close to 9,800 employees and close to 1,500 branches in Spain. They have not given any details of potential staff reductions or branch closures.

($1 = 0.8401 euros) (Reporting by Jesús Aguado; Editing by Emma Pinedo and Richard Chang)