According to preliminary polls, 40% of those registered were undecided to vote among social democrats, conservatives, liberals, environmentalists, far-right or left-wing parties in an intricated voting system.
Germany´s Social Democratic Party (SPD) candidate Olaf Scholz said he had a chance to lead the future German government by casting his vote at a college in the city of Potsdam, Brandenburg, said local television.
Polls released on saturday gave SPD a 25% preference, just two points above the conservative alliance in power formed by the Christian Democratic and Social Christian Unions of Bavaria (CDU / CSU).
The CDU / CSU candidate and Head of Government of North Rhine-Westphalia Armin Laschet called for a greater participation of all voters in an electoral process he branded as historically significant.
For the first time in 16 years, Angela Merkel abstained from running for office, after serving four terms in a row, but polls do not favor Laschet, her potential successor.