The Germany foreign minister, Frank-Walter Steinmeier, is likely to take over as the country’s president early next year after securing cross-party backing from Angela Merkel’s conservatives, a move expected to trigger a significant reshuffle at the top of German politics.

The parties that form Germany’s coalition government on Monday agreed to put forward the senior Social Democrat politician as their candidate to take up the presidency from 12 February, ending weeks of wrangling between the centre-right and the centre-left.

Steinmeier, a former SPD party leader, vice-chancellor in Merkel’s second coalition government and runner-up in the 2009 elections, has consistently received some of the highest popularity ratings in German politics but was opposed as a candidate by the chancellor until she struggled to field her own candidate.

Merkel said on Monday that Steinmeier was “excellently suited” to the post. “At a time when there’s unrest and instability around the world, sending a signal of stability - and so the conservatives supporting Steinmeier’s candidacy - is in my view right and important,” she said.

While the role is mostly ceremonial, German presidents have some influence in setting the tone on foreign policy as well as retaining powers to veto laws they believe violate the constitution.

The outgoing president, Joachim Gauck, a former Protestant pastor in East Germany, spoke out against human rights abuses in Russia and Turkey and supported Merkel’s stance during the refugee crisis.

Steinmeier, 60, criticised Donald Trump as a “hate preacher” during the election campaign and warned last week that US foreign policy would become “more unpredictable” after the Republican candidate’s victory.

During his two stints in the foreign office Steinmeier sought to continue the Social Democratic tradition of investing in dialogue with Russia, and raised eyebrows this summer when he said western military exercises in eastern Europe could be seen as “sabre-rattling”.

Personal reasons are believed to have been a key factor behind the presidential candidacy for the experienced politician, who donated a kidney to his wife in 2010.

But with Germany gearing up for a general election in autumn 2017, Steinmeier’s nomination will trigger a strategically significant reshuffle. Martin Schulz, the president of the European parliament, is mooted by various media outlets as Steinmeier’s obvious successor in the foreign ministry, which in turn could help him gain a big enough national profile to compete as a candidate against Merkel in the federal elections.

In Germany the president is not elected directly by the people but the country’s federal convention, an assembly of federal and delegates state parliament MPs. While some parties, such as the German Left , oppose Steinmeier due to his links to the labour market overhaul of the Gerhard Schröder era, the centre-right and centre-left have a majority in the federal convention.