* Schulz not certain to get green light for talks with Merkel
* Some members want party to go into opposition to lick wounds
* Immigration is major point of contention (Updates with more detail)
BERLIN, Dec 7 (Reuters) - The leader of Germany's Social Democrats (SPD) was seeking on Thursday to convince his reluctant party that it has a duty to discuss forming a government under conservative Chancellor Angela Merkel, for the sake of German and European stability.
Germany, Europe's political and economic powerhouse, has been struggling to build a new government since a Sept. 24 national election in which Merkel's conservative bloc and the SPD both lost support, while the anti-immigrant AfD party surged into parliament, complicating the potential coalition combinations.
Merkel, her own political future on the line after 12 years at the helm, has made overtures to the centre-left SPD - her partner in government over the past four years - after her bid to form a coalition with two smaller parties failed.
SPD leader Martin Schulz, who initially said the party would go into opposition after seeing its time in the last Merkel-led "grand coalition" rewarded with bruising losses at the polls, must now convince his party to reverse that decision.
He will ask party members for their support to start talks with Merkel's conservatives next week, although negotiations are expected to last well into the New Year.
Schulz is due to speak at noon (1100 GMT) and members are then set to debate motions on what kind of negotiating mandate the party should have for the talks, with many expected to demand a high price in return for supporting Merkel.
"We don't know if this coalition will happen. One thing is certain - we can't just carry on as before," SPD parliamentary leader Andrea Nahles, told the Bild newspaper. "There are good reasons against and some in favour."
If Schulz fails to get support to discuss continuing the grand coalition, then the whole leadership of the SPD would be up for debate, Carsten Schneider, party whip in parliament, told German radio.
Schulz, himself up for re-election at the congress, faces particular pressure from the youth wing of the party, which opposes a repeat of the grand coalition.
In a motion for the congress, the youth wing said the SPD had a "historical responsibility" not to enter government since the far-right Alternative for Germany (AfD) party, which came third in September's election, would then become the official opposition.
Outside the congress centre, activists handed out red cards reading "No grand coalition".
Schulz, an advocate of deeper European integration, also wants to push Germany toward embracing French President Emmanuel Macron's ideas for closer cooperation on defence, migration and euro zone economic governance.
On the issue of immigration, one of the main reasons for the collapse of Merkel's first attempt at a coalition, the SPD opposes a conservative plan to extend a ban on the right to family reunions for some accepted asylum seekers.
But SPD vice-president Aydan Ozoguz warned against "repeated skirmishes" over refugee rights, noting that Germany was no longer receiving hundreds of thousands of refugees from the Middle East as it had in 2015. (Additional reporting by Emma Thomasson; Editing by Kevin Liffey)