Germany looks set to join the Netherlands as the latest European giant to suffer a post-election crisis.
There is widespread concern that a lack of unity among the different parties will mean coalition talks could take several months.
An unstable coalition in Germany, largely seen as the economic engine behind the EU, could spark concern across the continental bloc.
Germans are going to the polls today to elect their latest leader, with Merkel odds-on favourite to clinch her fourth-term as Chancellor.
She is seeking to keep her conservative CDU/CSU alliance as the largest presence in Germany’s parliament.
However, the coalition building between national parties looks far from simple after a surge in the far-right Alternative for Germany Party.
Mrs Merkel’s closest rival, SPD leader Martin Schulz, has already ruled out any possibility of a coalition with the incumbent leader.
Speaking on BBC’s Dateline, Thomas Kiplinger, from Die Welt, said the real battle in German politics starts on Sunday evening.
He said: “The fight will over who is in coalition with Angela Merkel. That will be a long drawn-out wrangling, that could last at least until Christmas.
“Germany won’t be governed by anyone besides teachers, tax-collectors, the professional class – and its the same in Netherlands, they still don’t have a government.
“Belgium suffered the same issue as well a few years ago. Europe is struggling to form stable regimes.”
Mr Kiplinger added that Germany was increasingly uncomfortable with being seen as a responsible leader on the world stage.
He said: “We don’t want to be leaders in Germany, we want to stop the world and get off. The international climate, our neighbours, it’s turbulent.
“That is partly why Merkel doesn’t want to lose Britain under her watch. She doesn’t like Britain drifting away.
“They have been a key partner in free trade and similar cultures. She will only be left with problematic countries with Spain, France and those in the Mediterranean.”
Polling stations in Germany will close at 6pm this evening, with exit polls expected shortly after.