(CNN) -- Exit polls suggest German Chancellor Angela Merkel is heading for defeat in a key regional election seen by many as a protest vote over her handling of the Greek economic crisis.
An exit poll by the ZDF television channel following Sunday's vote in the North Rhine Westphalia state put Merkel's Christian Democrats (CDU) on 34.5 percent and their Free Democrat (FDP) allies on 6.5 percent, depriving Merkel of a majority in the Bundesrat, Germany's upper legislative chamber.
The exit polls suggest Germany's main opposition party the Social Democrats (SPD) won a projected 34.5 percent of the vote and the allied Green Party 12.1 percent, giving them a majority.
The CDU and FDP have ruled in North Rhine Westphalia since 2005, when they won 44.8 percent and 6.2 percent of the vote respectively.
The loss of a CDU-FDP majority in the federal upper house would mean Merkel will have to rely on opposition parties for support for her policy program, which includes tax cuts, health reform and extending the working life of some nuclear power plants.
Opposition parties have attacked Merkel for her handling of the Greece crisis after she initially resisted granting aid due to massive popular opposition to a bailout.
The multi-billion Greek rescue package is extremely unpopular with the German public, which may have resulted in a loss of votes, some analysts suggest.