Berlin  - German President Horst Koehler has suspended ratification of the Lisbon Treaty following a request to wait from Germany's constitutional court, aides said in Berlin Monday.

Opponents of the European Union (EU) reform treaty have gone to the court demanding injunctions against its ratification. It may take until next year for the constitutional court to give a verdict.

The document has already won a blessing from both chambers of the German parliament, but needs a signature from Koehler for Germany's ratification to be complete. The treaty has been imperilled since it was rejected by Irish voters in a referendum.

Koehler's functions are mainly ceremonial, but he has sometimes used his limited powers to block government legislation.

"In view of the applications for injunctions, the president has acceded to a request from the constitutional court," a statement by Koehler's office said.

The injunctions are being sought by Peter Gauweiler, a maverick federal deputy in Bavaria's Christian Social Union (CSU), and the Left Party. The Left claims the treaty breaches parliamentary rights.

Court officials in the southern justice capital of Karlsruhe said no hearing date had been set, though judges wanted to deal with the issue speedily. The justices must read the documents and first decide whether or not to hear the case, which could take many months.

In 2006, Koehler also delayed his signature to a forerunner of the Lisbon Treaty. That constitutional treaty subsequently collapsed when it was rejected by Dutch and French voters. (dpa)