A spokesman for Finance Minister Wolfgang Schäuble told a regular news briefing that the figure, reported by Der Spiegel magazine over the weekend, was unrealistic and "completely illusory."
While there were discussions in Brussels over boosting the firepower of the European Stability Mechanism (ESM), due to come into force next month with a volume of €500 billion, it would be "abstract" to discuss figures, said the spokesman, Martin Kotthaus.
"It's not feasible" to put a precise number on the potential final amount of the fund, he said.
However, he said that the German government backed in principle the idea of leveraging the fund, which is reported to have run into opposition from Finland.
The possibility exists already for the ESM's predecessor, the European Financial Stability Facility (EFSF), Kotthaus recalled.