Polling stations have opened across Germany in an election that is likely to see Chancellor Angela Merkel win a historic fourth term and a far-right party enter parliament for the first time in more than half a century.
Some 61.5 million people are eligible to cast their ballots in the election in which Merkel's Christian Democrats (CDU) are expected to post a commanding lead over their centre-left Social Democrat (SPD) rivals.
Merkel's conservative bloc is on track to remain the largest group in parliament, opinion polls indicated, but a fracturing of the political landscape may well make it harder for her to form a ruling coalition than previously.
With as many as a third of Germans undecided in the run-up to the election, Merkel and her main rival, centre-left challenger Martin Schulz of the Social Democrats (SPD), urged them to get out and vote.
"We want to boost your motivation so that we can still reach many, many people," the chancellor, 63, said in Berlin on Saturday before heading north to her constituency for a final round of campaigning.
In regional votes last year, Merkel's conservatives suffered setbacks to the hard-right Alternative for Germany (AfD), which profited from resentment at her 2015 decision to leave German borders open to over one million migrants.
Those setbacks made Merkel, a pastor's daughter who grew up in Communist East Germany, wonder if she should even run for re-election.
But with the migrant issue under control this year, she has bounced back and thrown herself into a punishing campaign schedule, presenting herself as an anchor of stability in an uncertain world.
Visibly happier, Merkel campaigned with renewed conviction: a resolve to retool the economy for the digital age, to head off future migrant crises, and to defend a Western order shaken by Donald Trump's US election victory last November.
Both Merkel and Schulz worry that a low turnout could work in favour of smaller parties, especially the AfD. On Friday, Schulz described the AfD as "gravediggers of democracy".
An INSA poll published by Bild newspaper on Saturday suggested that support was slipping for Merkel's conservatives, who dropped two percentage points to 34 per cent, and the SPD, down one point to 21 per cent - both now joined in an unwieldy "grand coalition".
The anti-immigrant AfD rose two points to 13 per cent, putting it on course to be the third-largest party.
Should she win a fourth term, Merkel will join the late Helmut Kohl, her mentor who reunified Germany, and Konrad Adenauer, who led Germany's rebirth after World War II, as the only post-war chancellors to win four national elections.
The AfD's expected entry into the national parliament is likely to herald an era of more robust debate in German politics - a departure from the steady, consensus-based approach that has marked the post-war period.
