The European Central Bank does not have unlimited firepower to handle Europe's debt woes, Germany's Vice-Chancellor and Economy Minister Philipp Roesler said on Friday.
Speaking at an event in Berlin, Roesler said that if the ECB opened its floodgates fully, they could never be closed again.
He rejected suggestions that the bank print money to help heavily indebted euro zone states. This might help in the short term, Roesler said, but the impetus to create lasting stability and make reforms would disappear.
To date, the ECB has distinguished itself from the U.S. Federal Reserve and the Bank of England by refraining from embarking on a policy of 'quantitative easing' -- code for printing more money.
Instead, the ECB sterilises -- or neutralises -- its bond buys by conducting weekly liquidity absorbing operations equal to the cumulative size of its debt purchases.
The bank is under growing pressure however from world leaders to do more to address the crisis which has now engulfed major debtor Italy.
Despite the intensification of the crisis, it has not delivered the kind of 'shock and awe' intervention that could calm markets. The bank is reluctant to take more risk onto its books by buying more bonds from debt-laden euro zone countries.
Germany's central bank, the Bundesbank, has opposed the ECB's bond-buying programme of paper from heavily indebted euro zone states, arguing this compromises the independence of the bank.
As for the different interest rates in sovereign debt issued by members of the euro currency bloc, Germany's Roesler said they provided states with a motive to make structural reforms.
Italy, he mentioned as an example, showed earlier this year that its appetite for reforms could wane if the ECB's bond buying reduced risk premiums on sovereign debt.
(Reporting by Andreas Rinke; Editing by Ruth Pitchford)