Chancellor Angela Merkel travels Saturday to Aachen, hometown of her would-be successor Armin Laschet, in a last-ditch push to shore up his beleaguered campaign 24 hours before Germans vote.

Laschet, 60, has been trailing his Social Democrat challenger Olaf Scholz in the race for the chancellery, although final polls put the gap between them within the margin of error, making the vote one of the most unpredictable in recent years.

Merkel had planned to keep a low profile in the election battle as she prepares to bow out of politics after 16 years in power. But she has found herself dragged into the frantic campaign schedule of the unpopular chairman of her party, Laschet.

In the last week of the campaign, Merkel took Laschet to her constituency by the Baltic coast and on Friday headlined the closing rally gathering the conservatives' bigwigs in Munich.

Merkel tugged at the heartstrings of Germany's predominantly older electorate on Friday, calling them to keep her conservatives in power for the sake of stability -- a trademark of Germany.

"To keep Germany stable, Armin Laschet must become chancellor, and the CDU and CSU must be the strongest force," she said.

A day before the vote, she will accompany Laschet to his constituency Aachen, a spa city near Germany's western border with Belgium and the Netherlands, where he was born and still lives.

At the other end of the country, Scholz will be holding "dialogues on the future" with voters in his constituency of Potsdam -- a city on the outskirts of Berlin famous for its palaces that once housed Prussian kings.

'Could backfire' 

Scholz, currently finance minister from Merkel's junior coalition partners SPD, has avoided making mistakes on the campaign trail, and largely won backing as he sold himself as the "continuity candidate" after Merkel in place of Laschet.

Also on the campaign trail on Friday, Scholz demanded a "fresh start for Germany" and "a change of government" after 16 years under Merkel.

Described as capable but boring, Scholz has consistently beat Laschet by wide margins when it comes to popularity.

But with the clock ticking down to election day, Laschet's conservatives were closing the gap, with one poll even putting them just one percentage point behind the SPD's 26 percent.

Laschet had gone into the race for the chancellery badly bruised by a tough battle for the conservatives' chancellor candidate nomination.

Nevertheless, his party had enjoyed a substantial lead ahead of the SPD heading into the summer.

But Laschet was seen chuckling behind President Frank-Walter Steinmeier as he paid tribute to victims of deadly floods in July, an image that would drastically turn the mood against him and his party.

With the conservatives running scared as polls showed the race widening for the SPD, they have turned to their greatest asset -- the still widely popular Merkel.

Yet roping in the chancellor is not without risks, said political analyst Oskar Niedermayer of Berlin's Free University.

"Merkel is still the most well-liked politician. But the joint appearances can become a problem for Laschet because they are then immediately being compared to each other," he said.

"And it could therefore backfire because people could then think that Merkel is more suitable than Laschet."