A miniature copy of Germany's constitution lies on top of a printed version of the European Union's Lisbon treaty at a lawyers desk prior to the announcement of the verdict on a clutch of legal challenges against Germany's ratification of the European Union's Lisbon Treaty at Germany's constitutional court in Karlsruhe, June 30, 2009. [Photo: Xinhua/Reuters]

Related: Barroso Welcomes German Court's Ruling on Lisbon Treaty

Germany's Constitutional Court on Tuesday delayed ratification of the planned European Union (EU) reform treaty but said the measure meets legal guidelines.

The Lisbon Treaty has already been approved by both houses of the German parliament, but 50 opposition lawmakers claimed the proposal was undemocratic and appealed to the Karlsruhe-based court to decide if it violated the country's constitution by giving up too much power to the EU.

The Constitutional Court ordered lawmakers to rewrite national legislation enacting the treaty that is meant to streamline how the 27-nation bloc is run and bolster its role on the world stage.

"The basic law says yes to the Lisbon Treay but demands at national level a strengthening of the parliament's involvement," Andreas Vosskuhle, the presiding judge, said in a televised ruling.

President Horst Koehler has declined to sign the measure. He has been waiting for the decision from the court.

The draft governing charter, also known as the Lisbon Treaty, was signed by all 27 EU leaders in 2007. If unanimously adopted by all EU states it would reshape EU institutions and decision-making procedures, handing more powers to the European Parliament and create the post of an EU president, who would preside over summits and represent the bloc on the world stage.