HELSINKI (Reuters) - Big bank depositors could take a hit under planned European Union law if a bank fails, the EU's economic affairs chief Olli Rehn said on Saturday, but noted that Cyprus's bailout model was exceptional.

"Cyprus was a special case ... but the upcoming directive assumes that investor and depositor liability will be carried out in case of a bank restructuring or a wind-down," Rehn, the European Economic and Monetary Affairs Commissioner, said in a TV interview with Finland's national broadcaster YLE.

"But there is a very clear hierarchy, at first the shareholders, then possibly the unprotected investments and deposits. However, the limit of 100,000 euros is sacred, deposits smaller than that are always safe."

The European Commission is currently drafting a directive on bank safety which would incorporate the issue of investor liability in member states' legislation.

To secure a 10 billion euro EU/IMF bailout last month, Cyprus forced heavy losses on wealthier depositors. Initially it had also pledged to introduce a levy on deposits of less than 100,000 euros - even though they are supposedly protected by state guarantees - before reneging in the face of widespread protests.

Rehn also said that the European Central Bank should launch fresh action to help boost the recession-hit euro zone economy.

ECB President Mario Draghi, at a press conference on Thursday, opened the way for the bank to possibly cut interest rates and to take fresh 'non-standard measures' - steps other than classic rate moves, such as government bond purchases or funding operations like the twin three-year loans it offered banks just over a year ago.

Rehn said that high financing costs for companies, especially in southern Europe, were a major problem right now.

"Therefore, the ECB's talk on Thursday about both standard and non-standard measures is very important because the ECB may have a role in making the situation easier," Rehn said.

(Reporting by Jussi Rosendahl; Editing by Susan Fenton)