Greeks are pulling their cash out of banks and stocking up with food ahead of an election on Sunday that many fear will result in the country being forced out of the euro.
Bankers say up to €800 million are leaving major banks daily.
Retailers say some of the money is being used to buy pasta and canned goods, as fears of returning to the drachma are fanned by rumours a radical leftist leader may win the election.
The last published opinion polls showed the New Democracy party, which backs a €130 billion bailout that is keeping Greece afloat, running neck and neck with the Syriza Party, which wants to cancel the rescue deal, Reuters reports.
Greece has only enough cash to last for a few weeks.
Central bank figures show deposits shrank by about 17%, or €35.4 billion in 2011 and were €165.9 billion at the end of April.
Bankers said the pace was picking up ahead of the vote. Combined daily deposit outflows from the major banks have been €500 million and €800 million over the past few days, and €10 million to €30 million at smaller banks.