Mrs Merkel's failure to form a coalition since September's inconclusive election means Germany has been without a government for 13 weeks.

According to a YouGov survey, almost half of voters now want the Chancellor to quit her four-year term early if she remains in power.

Of the 2,036 respondents, 47 per cent of wanted Mrs Merkel to resign before 2021, up from 36 per cent in a poll taken in October.

And 36 per cent wanted the Christian Democratic Union (CDU) leader to serve a full term, compared to 44 per cent three months ago.

The survey, commissioned by the DPA news agency and published in the newspaper Die Welt, make for unpleasant reading for Mrs Merkel.

She lost swathes of support to the far-right Alternative for Germany (AfD) in September's election, leaving her party short of a majority.

Talks about forming a three-way coalition with the Greens and the pro-business Free Democratic Party collapsed in November.

Mrs Merkel is now pinning her hopes on cutting a deal with the Social Democrats (SPD), who finished second in the election.

But the centre-left has so far given a lukewarm response to the idea of renewing a 'grand coalition' with Mrs Merkel's party.

The SPD's Foreign Minister Sigmar Gabriel today urged the Chancellor to accept his party's calls for further reform of the Eurozone. 

He told Bild: "If the chancellery continues to reject all the proposals for EU reform, there will be no coalition with the SPD."

The SPD's current leader Martin Schulz is an arch Europhile who has called for the EU to create a "United States of Europe" by 2025.

Speaking earlier this month, Mr Schulz pushed for a new "constitutional treaty" to establish a federal union.

The ex-European Parliament president warned: "Such a constitutional treaty has to be written by a convention that includes civil society and the people. 

"This constitutional treaty will then have to be put to the member states and those that don't approve it will automatically have to leave the EU."