BERLIN, Dec. 22 (Xinhua) -- Andrea Nahles, leader of the parliamentary faction German Social Democrats (SPD), wants to see taxes on top income earners lifted in exchange for her party's participation in another "grand coalition", the magazine "SPIEGEL" reported on Friday.

Nahles demanded concrete concessions from the Christian Democratic Union (CDU) and Christian Social Union (CSU), telling "SPIEGEL" that the SPD would "not elect Merkel to the chancellery again because of a few headlines."

Official negotiations between the SPD, CDU and CSU over the formation of a new German government are due to commence in early January.

"We must consider how top income earners can contribute more to the financing of state services", Nahles said. Higher tax rates and an additional "rich tax" were two options which could help achieve this objective.

The SPD parliamentary faction leader further called for the fiscal burden on capital and labor to be equalized, as well as eliminating what she described as a "two-class-system" in public healthcare.

However, the acting Finance Minister Peter Altmaier (CDU) told the newspaper "Sueddeutsche Zeitung" that higher taxes and more public debt were not desired by the CDU and CSU. Instead, the conservative sister parties wanted to lower the fiscal burden on lower- and middle-income earners.

Nevertheless, Altmaier said that the CDU and CSU "would not draw any red lines in public" before the start of coalition talks.

Altmaier argued that the next federal government should focus on achieving higher tax revenue through economic growth. The finance minister expressed his confidence that such a deal could be reached with the SPD, not least because he believed that many of its members were open to a program of public investment which did not require raising new debt.

A shared legislative platform which "adequately addressed the great future challenges of the country" would also have to increase the availability of affordable housing through additional construction in the coming years according to Altmaier.

The CDU politician also listed improved internet speed in Germany and more government support for families and children as common ground between the SPD, CDU and CSU.

Chancellor Angela Merkel (CDU), CSU leader Horst Seehofer and SPD leader Martin Schulz will meet for a first round of preliminary talks shortly after the German Christmas holidays on Jan. 3. Official talks are subsequently scheduled to take place between Jan. 7 and 12.