Merkel attends the first Bundestag session since the collapse of government coalition talks on November 21 | Sean Gallup/Getty Images Germany’s SPD sets out conditions for joining Merkel in government Social Democrat leaders called on chancellor’s conservatives to ‘build trust’ before potential talks.

Germany's Social Democrats have started to lay out their demands for partnering with Angela Merkel's conservative party after backing off their refusal to enter into a coalition with her government, German media reported Sunday.

The SPD is considering reprising its role of the past four years as a junior partner in the government or supporting a minority administration. Talks to establish a three-way coalition between Merkel's conservative bloc, the Greens and the liberal Free Democrats collapsed a week ago.

Speaking to German newspaper Welt am Sonntag, the Social Democrats' secretary for family affairs, Elke Ferner, called on Merkel's conservative bloc to reconsider social policies it had blocked in a previous coalition agreement, including a tax-financed supplementary pension for people with low pension entitlement, as a way to "build trust" between the parties.

SPD Deputy Chair Karl Lauterbach implied that the abolition of private health insurance would be a prerequisite for negotiations, saying if Merkel's conservative alliance doesn't move on the issue "we have no chance of preventing new elections."

"We'll see if [Merkel's conservative alliance] is ready to move in the direction of a fair country," he said.

Migration and refugee policies are also a major sticking point, according to party deputy Ralf Stegner. The SPD, he said, could not get on board with the upper limit on refugee arrivals Merkel's Christian Democrats agreed with their Bavarian sister party, the Christian Social Union (CSU).

"An upper limit on refugees still goes against the constitution and the Geneva Refugee Convention," Stegner told the Funke media group. "That's why the SPD won't agree to an additional limit on the right to family reunification."

The party's leader in Rhineland Pfalz, Alexander Schweitzer, also laid out several demands, calling for more investment in education, housing and broadband, as well as relief to indebted communities. He also set serious debate over public insurance as a pre-condition for coalition talks, die Welt reported.

"If the government doesn't change course here, we can spare ourselves any further discussions," Schweitzer said, adding that a new grand coalition between the CDU and SPD was currently still "out of reach."

"Merkel is not in a position to make demands," cautioned SPD politician Malu Dreyer.

Also on Sunday, CSU chief Horst Seehofer told Bild am Sonntag a new coalition with the SPD "is the best option for Germany."

The Bavarian party's leader said he welcomed the Social Democrats' willingness to consider joining Merkel's government, but warned against setting too many red lines ahead of negotiations. "There cannot be a grand coalition at any price," he said.