BERLIN (Reuters) - Negotiators thrashing out a new coalition deal between Chancellor Angela Merkel’s conservatives and the Social Democrats (SPD) aim to wrap up talks by next weekend, in a sign Germany’s months-long political limbo could be nearing an end.

In a joint statement made after the first morning of formal coalition talks on Friday, the parties said expert groups would aim to assemble a concrete governing program for Europe’s largest economy within seven days.

“From Friday to Sunday (next week), top negotiators will meet with the aim of finalizing the negotiations,” they said, adding that they were making room for two further days of the highly sensitive talks in case of timetable slippage.

German Chancellor Angela Merkel’s conservatives opened coalition talks with their Social Democrat (SPD) partners on Friday, promising swift progress in negotiations aimed at ending four months of political limbo in Europe’s largest economy.

Four months after a national election that returned a fragmented German parliament, the tight timetable is an indication parties are anxious to bring an end to a period of rudderlessness that critics say has fueled the far-right.

“People expect us to move towards forming a government and that’s why I’m very optimistic and very determined,” said Merkel on arrival at the talks on Friday morning. The talks are her best hope of securing a fourth term after the failure of an earlier attempt to form a three-way coalition.

While most experts expect talks to succeed, many in the SPD are reluctant, seeing a repeat coalition as at best a painful sacrifice by their party for the sake of stability in Europe’s economic and political behemoth.

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Appealing to them, leader Martin Schulz stressed their party’s global responsibility.

“Given the challenges from China and the U.S., the European Union needs a strong, pro-European Germany,” he said. “And that you will only get if the SPD is in government.”

CONFLICTS

But Stephan Weil, SPD premier of the state of Lower Saxony, said the party must define itself more clearly against the conservatives in any future coalition with Merkel, promising a more tempestuous approach.

“The SPD has to become sharper, more critical and more willing to take on conflicts than it has been,” he told news magazine Der Spiegel.

Underlining the stakes for the SPD, one of two main parties that dominated post-war German history, a poll for ARD television showed only 19 percent would vote for it in repeat elections, placing it just seven points ahead of the far-right Alternative for Germany (AfD).

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Riven by division over whether it would not be better to rebuild in opposition, the SPD’s leadership is under pressure from its radical youth wing to win concessions from the conservatives, on immigration in particular.

But the conservatives also want to stand their ground to defend their right flank from the AfD, which burst into parliament for the first time on Sept. 24, propelled by public concerns over Merkel’s decision to open Germany’s doors to more than a million refugees in 2015.

In a draft agreement the two camps hammered out this month, the parties agreed a soft ceiling of 220,000 immigrants a year, one the Christian Social Union (CSU), arch-conservative Bavarian sister party to Merkel’s CDU, refuses to compromise on.

Senior SPD member Democrat Andrea Nahles told broadcaster ARD her party would push for worker-friendly social justice measures like eliminating many fixed-term contracts and improving conditions for citizens who pay into the public rather than private healthcare system.

But time presses. The SPD membership has been promised a vote on a final coalition deal. With new members thronging to the party in the hope of casting a vote against a new coalition, chances of securing membership consent diminish by the day.