The unanimous vote came after the lower house, the Bundestag, approved admission of the two countries in a separate vote taken at the end of October.

Made up of representatives from Germany's 16 states, the Bundesrat also endorsed a resolution enabling the EU to postpone the countries' accession if their judicial systems and efforts to combat crime are not up to European standards.

Both houses of German parliament said it should be possible to enforce this provision upon the eastern European nations' membership in the bloc if their reform efforts do not reach EU standards.

Lower Saxony Premier Christian Wulff of the Christian Democratic party urged Romania and Bulgaria after the vote to continue with reforms and said their membership would be met "with open arms and without provisions." He also added, however, that Bucharest and Sofia were receiving an "advance of trust" they would need to prove they deserved as EU members.

Bundesrat also in favor of EU Constitution

In a separate decision, the German upper chamber also unanimously approved a resolution maintaining the "legal and political substance" of the draft EU constitution.

The motion calls for Germany to use its EU presidency in the first half of 2007 to give an "important push to the revitalization of the constitutional process."

The constitution draft was rejected by referendums in France and the Netherlands in 2005, but Germany has announced it plans to make establishing a blueprint for the document's revival a central part of its presidency.