Earlier, Draghi's lieutenant at the ECB, Benoit Coeure, said governments could help counteract lower prices with "fiscal policy, when it is available without questioning long-term debt sustainability" - a cue for governments like Germany to invest.
The discord between the hawkish Weidmann and policymakers closer to Draghi such as Coeure highlights deep divisions within the Council about how far the ECB should go to support the economy, and comes just as jittery markets look for reassurance.
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Weidmann brushed off the suggestion that more German public investment could help other euro zone economies, and also took aim at ECB plans to buy asset-backed securities, or bundled loans -- a dig that a further ECB policymaker rejected.
"The boost to the peripheral countries from an increase in German public investment is ... likely to be negligible," Weidmann told a conference in Riga, where Coeure also spoke.
"And with the economy operating at normal capacity utilisation, Germany is not in need of stimulus either -- and this will remain the case with the revised forecasts that still foresee growth in line with potential," he added.
On Tuesday, German Chancellor Angela Merkel rejected calls for Berlin to ditch its plans for a balanced budget next year.
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In a landmark speech in late August, Draghi signalled he was ready for the ECB to deploy further stimulus. But he also called for governments to shape up their economies with structural reforms, saying "it would be helpful for the overall stance of policy if fiscal policy could play a greater role".
The ECB duly cut interest rates to record lows and unveiled a plan to buy private-sector assets -- covered bonds and asset-backed securities (ABS) -- but Berlin is reluctant to spend more and other governments are taking time with structural reforms.
Bad bank debate
Draghi hopes the purchases of ABS will stimulate the market for such securities and support the economy by offering companies an alternative source of credit.
Weidmann said such ABS purchases "are problematic when they imply a transfer of risks from banks to the balance sheet of the central bank".
"In the end, this could amount to a transfer of risks from banks to the taxpayer," he added.
In Vienna, another ECB Council member, Austrian central bank chief Ewald Nowotny, dismissed as "nonsense" concerns the ABS purchases will transfer risk from lenders to the ECB.
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"This discussion, about the ECB becoming a 'bad bank', is washing over from Germany to us here," Nowotny told reporters. "Speaking quite plainly, that is nonsense because when we look at the balance sheet of the ECB the possible portion of ABS is so small ... that it is in no way to compare with a 'bad bank'."
Coeure said the ECB would begin buying ABS within days. He and Nowotny sought to reassure about the outlook for the euro zone in a week that has seen its stocks and bonds back in the firing line due to stagnating growth, low inflation, budget problems in France and Italy and political risks in Greece.
Coeure, who sits on the six-member Executive Board that forms the nucleus of the broader Governing Council, said the euro zone was still on a recovery path.
"We expect growth to be positive in the third quarter and the fourth quarter in the euro zone," he added.
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Both men said the ECB could act again if needed. "One surely has further opportunities," said Nowotny. "I may point out we are not in recession, we have positive growth rates. It is not as if the ECB has to open the emergency pharmacy now."
In Zurich, ECB Executive Board member Yves Mersch said: "a central bank with a clear mandate to safeguard price stability needs to act forcefully when push comes to shove."
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