FRANKFURT (Reuters) -A digital euro could drain up to 700 billion euros ($810.88 billion) in deposits during a run on commercial banks, pushing around a dozen euro zone lenders into a liquidity squeeze, a European Central Bank simulation showed on Friday.

The study, requested by European legislators, was aimed at evaluating the risks that a digital currency, essentially an electronic wallet guaranteed by the ECB, would pose to the banking sector under different scenarios, including a hypothetical "flight to safety".

The ECB has presented the digital currency as an alternative to U.S.-dominated means of payment, but bankers and some lawmakers fear it may empty banks' coffers.

The ECB's study found that, were there to be an unprecedented run on commercial banks, depositors would withdraw 699 billion euros from euro zone banks to park them in digital euros if a limit on individual holdings was set at 3,000 euros each.

This is equal to 8.2% of all retail sight deposits, although the impact would be greater for small market lenders and retail banks, the ECB said.