Germany's Vice-Chancellor Philipp Roesler on Friday said the European Central Bank did not have unlimited firepower to handle the bloc's debt woes.
Speaking at an event in Berlin, Roesler added that if the ECB opened its floodgates fully, they could never be closed again.
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.
(Reporting by Andreas Rinke; Editing by Ruth Pitchford)
(This story was corrected in 3rd paragraph to make clear Bundesbank rather than federal government opposed ECB bond-buying)