German Chancellor Angela Merkel's party was in the lead after the first state poll in a general election year, initial
results have shown, but the race for a ruling coalition rested on a knife-edge.
Preliminary results from Lower Saxony on public television showed Merkel's Christian Democrats (CDU) ahead with around 36 percent and their coalition partners for the last decade, the Free Democrats (FDP), with about 10 percent in Sunday's elections.
Citizens in the northern state began voting at 07:00 GMT, in what had been predicted to be a close battle between Merkel's centre-right coalition and the Social Democrat (SPD)-Greens opposition.
In exit polls released after voting ended at 1700 GMT, CDU remained the biggest party in Lower Saxony with about 36 per cent while their FDP allies beat all expectations with 10 per cent.
About 6.1 million people were eligible to vote for the new state legislature.
Led by David McAllister, state premier, the CDU and their Free Democrat allies had drawn even in opinion polls with their opponents, each on 46 per cent, even though the centre-right trailed by 13 points in voter surveys through mid-2012.
"The winds in Lower Saxony have turned and you can feel that everywhere you go," McAllister told German TV after a rally.
Merkel, the most popular politician in Germany thanks to her handling of the eurozone debt crisis, hopes a victory for the centre-right in Lower Saxony, an industrial and farming heartland, would give her re-election campaign a boost ahead of the September federal vote.
The comeback in Lower Saxony has turned Germany's fourth-most populous state - a genuine swing state - into a ferocious battleground with Merkel appearing seven times to campaign with McAllister, the West Berlin-raised son of a British soldier.
The SPD and the Greens, who had long been comfortably ahead of the centre-right incumbents in polls, have watched as their lead has evaporated. Stephan Weil, the local SPD leader, has been hurt by gaffes of Peer Steinbrueck, the SPD chancellor candidate.
In a sign of the party's nerves, Steinbrueck and Sigmar Gabriel, the SPD leader, met privately on Friday to discuss how to react to a defeat, German media reported.