According to Spiegel, Nahles requested the new tax law from the Christian Democratic Union (CDU), and the Christian Social Union (CSU), claiming that the SPD would "not elect Merkel to the chancellery again because of a few headlines."
Negotiations between the SPD, CDU and CSU over a new German coalition government are to begin next month.
"We must consider how top income earners can contribute more to the financing of state services," Nahles said, arguing that higher tax rates and a "rich" tax would help Germany attain that goal.
Nahles also urged for the elimination of the "two-class-system" in public healthcare, in which a government-sponsored program provides basic care and a secondary tier of care is offered to those who can afford to pay extra.
German Finance Minister Peter Altmaier (CDU) claims that his party and CSU policies aim to diminish the fiscal burden on lower and middle income earners. However, Altmaier said that the CDU and CSU "would not draw any red lines in public" before the coalition talks start in January.
Altmaier also urged Germany's next federal government to attain higher tax revenue through economic growth, adding that a shared legislative platform could increase affordable housing through increased construction over the next several years.
The CDU politician also called for faster internet speed and additional government support for families and children to be common goals offered by all the three parties.
