The managing director of the European Stability Mechanism (ESM), Klaus Regling, insisted that Spain's exit from its bank bailout program was not premature.
In an exclusive interview with CNBC, Regling, who heads up the euro zone's emergency bailout fund, said Spain's banks were now "well-restructured."
Last week, the euro zone's finance ministers agreed to let Spain exit the financial aid program provided for its banks in 2012.
(Read more: ECB's Draghi: New bank stress tests 'just the beginning')
The country used 41 billion euros ($55.4 billion) of the 100 billion euros available to rescue a number of its banks that had come close to collapse. Losses at banks such as Bankia had threatened the government's finances.
When asked whether it was too soon for Spain to leave the program, Regling told CNBC: "Not to the best of my knowledge."
He added: "It would be very surprising if after all the scrutiny through which the Spanish banks went in the context of the ESM program… if there were surprises now – we don't really expect that. These banks are well-restructured."
(Read more: Europe's banks face$95 billion funding shortfall)
To take the burden of rescuing banks off the shoulders of governments in the future, European leaders have agreed to create a region-wide banking union which will provide supervision of the financial sector on a pan-European level.
The European Central Bank will take over as the region's banking watchdog -- under the "Single Supervisory Mechanism" – in November 2014, after conducting so-called stress tests on the region's banks.
Regling said the European Stability Mechanism could play "several roles" as part of this banking union.
(Read more: Spanish banks abuy for first time 'in years')
"We can play our traditional role… We can provide macro-economic adjustment programs, finance these programs," he said, adding there was "always an important component for banking."
Regling gave the example of Greece's bailout, which included a 50 billion euro component earmarked for bank restructuring. "So this could happen again if necessary," he said. Similarly, the financial assistance provided to stump up Spain's financial sector, "could be repeated."
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