Chancellor Angela Merkel has been warned by potential coalition partners she faces a tough task in pulling together a workable German government.
“Politics is not mathematics,” warned the leader of the business-friendly FDP, Christian Lindner, seen as a natural coalition ally.
In a separate, dramatic development, Finance Minister Wolfgang Schäuble was reported to have lost his job,
He will take on the role of president of the Bundestag, sources say.
Mr Schäuble, 75, has long been seen as an influential figure in the eurozone and a leading advocate of austerity measures.
Choosing his successor will now become an important part of coalition talks. The finance ministry is known to be coveted by the FDP, and could be filled by Mr Lindner.
Meanwhile, German commentators suggested Mr Schäuble could use his political experience to control heated debates in parliament involving the right-wing nationalist AfD.
Uncertainty after the German election sent the euro to its lowest level for a month on Wednesday.
The most likely coalition for the chancellor’s Christian Democrat CDU is with the FDP and the Greens. If she fails to reach a deal in coming months, Germany could face fresh elections.
‘Change of course’
Mr Lindner told Die Welt newspaper that the arithmetic added up for a coalition with Mrs Merkel’s party and the Greens, but his party’s election mandate required “a change of course in German politics”.
With the centre-left Social Democrats ruling out a coalition, the only deal likely to work would be a so-called Jamaica coalition, named after the black, yellow and green colours of the parties involved: the black CDU, yellow FDP and the Greens.
Mr Lindner, whose party disagrees with the Greens on Europe, education and migrant policy, accused some people of turning “Jamaica” into a “romantic political project”.
Big differences on migrants
Mrs Merkel does not just face an uphill struggle with potential coalition partners.
She will also have to reach a compromise on immigration with the CDU’s sister party in Bavaria, the CSU, which suffered big losses in Sunday’s elections and faces a key vote for the Bavarian state assembly next year.
Bavaria is the arrival-point for most irregular migrants to Germany, and the right-wing nationalist AfD, which ran on an anti-immigration platform, picked up 12.4% of the vote, attracting voters from the CSU – which saw a fall in support of more than 10 percentage points to 38.8%.