Germany's Finance Minister Wolfgang Schaeuble said Monday he was confident the country's top court will not block the signing into law of the eurozone's key crisis-fighting tools.

"The constitutional court will not block, I am sure, the treaties of the fiscal compact and the ESM," he said, referring to the European Stability Mechanism and the European fiscal pact. The ruling is due on September 12.

Speaking at a conference in Strasbourg, the minister said the court will however closely examine if these treaties conform to basic German law.

"I can't see any problem with the German constitution," he added.

The German parliament voted in favour of the European Stability Mechanism (ESM) and the European fiscal pact with a two-thirds majority at the end of June.

But German President Joachim Gauck held off from completing the ratification process following a raft of legal challenges filed by the far-left Die Linke party, a citizens' initiative group and a well-known eurosceptic from Chancellor Angela Merkel's CSU Bavarian sister party.

They argued that the ESM -- the EU's permanent 500-billion-euro ($627-billion) rescue fund -- and the fiscal pact were incompatible with Germany's "Grundgesetz" or Basic Law because they are effectively forcing Germany to surrender its budgetary sovereignty without the necessary democratic backing.

They argue that by committing Europe's biggest economy and already its effective paymaster to the ESM, parliament was exposing Germany's public finances to unlimited risks should more eurozone countries topple under the debt crisis.