The BBC reports New election blow for Germany's Merkel
Chancellor Angela Merkel's conservatives have suffered heavy losses in an election in Germany's most populous state, exit polls suggest.
Support for the Christian Democrats dropped from 35% to 26% in North Rhine-Westphalia, with the Social Democrats set to return to power with the Greens.
It is the Christian Democrats' worst result in the state.
Analysts say many voters rejected Mrs Merkel's tough line on fiscal discipline as a cure for state debt.
In another development, the exit polls suggested Germany's Pirate Party had won seats in North Rhine-Westphalia, making it their fourth state parliament.
The Pirate Party has grown in strength recently with its calls for transparency and internet freedom.
According to two exit polls, the Social Democrats (SPD) won around 38%, the Christian Democrats (CDU) 25.5%, the Greens 12%, the Free Democrats (FDP) 8.5%, the Pirates 7.5% and the Left, 2.5%.
The FDP, the CDU's national coalition partner, performed better than expected, increasing their vote by nearly two percentage points and thereby giving the lie to speculation that they might fail to win seats.
When the CDU and FDP recently lost elections in the northern state of Schleswig-Holstein, Mrs Merkel's party scored its lowest tally there for 50 years.