Former German foreign minister Frank-Walter Steinmeier has been elected president by a parliamentary assembly.
German local media have long speculated Steinmeier as the obvious victor, since he got the grand governing coalition as well as the influential Social Democratic Party of Germany on his back.
The vote is due at 12:00 local time (CET).
Germany's president is not directly elected by the people, but by an assembly of 1,260 people - members of the federal parliament and special delegates from 16 regional parliaments, euronews reported on Sunday.
He will succeed Joachim Gauck, a 77-year-old former pastor and East German pro-democracy activist.
The German president has little executive power but is considered an important moral authority.
He has always been one of Germany's most popular politicians.
The 61-year-old, who regularly polls as Germany's most popular politician, will represent the EU's top economy overseas and act as a kind of moral arbiter for the nation.
During the USA election campaign, the usually circumspect former lawyer described Donald Trump as a "hate preacher" and predicted more challenging relations with Washington.
"Vladimir Putin reiterated commitment to continue constructive dialogue on topical issues of the bilateral and worldwide agenda and invited Frank-Walter Steinmeier to visit Russian Federation at any time convenient for him", the Kremlin press service said.
A policy wonk by nature, Steinmeier served as advisor and then chief of staff to Merkel's predecessor, the SPD's Gerhard Schroeder.
This story has been corrected from an earlier version to show the surname of Steinmeier's wife is Buedenbender, not Buedenbende.