Outflows spiked just after the inconclusive May 6 election, and have picked up in recent days ahead of Sunday's new vote, one official said Wednesday.
Since the Greek debt crisis broke in late 2009, depositors have slowly pulled some €72 billion ($90.24 billion) from local lenders, with total household and corporate deposits standing at €165.9 billion ($207.94 billion) in April, according to the latest data from the Bank of Greece.
Deposit outflows eased in March and April, following Greece's second international bailout and a massive writedown in its privately-held debt, but resumed in May after the election results. In a few days after the May 6 ballot, some €800 million ($1 billion) were pulled out.
Barroso's prescription of more union to solve the crisis also came under threat from Germany, Europe's largest economy, on Wednesday. Chancellor Angela Merkel and the country's opposition leaders failed to reach an agreement on a European growth initiative in a new round of talks, according to participants. That failure will hold up passage of a new Europe-wide treaty designed to ensure countries keep their budgets in check.
Merkel had been one of the main architects of that treaty, which for a time brought a calm to the crisis. That she is struggling to get the support of her own Parliament for it underscores how difficult any progress in Europe is.
Germany's Finance Minister Wolfgang Schaeuble on Wednesday stressed Europe must take advantage of the crisis and make bold steps to deepen its integration. "The time for large steps is now," he said.
Associated Press writers Colleen Barry in Milan, Al Clendenning in Madrid, Juergen Baetz in Berlin, and Nicholas Paphitis in Athens contributed to this report.