Germany's main opposition party said on Monday it wanted to create a "new social balance" in Europe's biggest economy, judging that the gap between rich and poor was growing and that financial markets needed greater regulation.
SPD candidate for chancellor, Peer Steinbrück, told a news conference that his party would introduce a "legal, flat-rate minimum wage of at least €8.50" if elected in federal election on September 22.
The SPD manifesto also stressed: "Markets need regulation. This is true especially for the financial markets, in which many products continue to be traded without controls - with dangerous consequences. The SPD will create these regulations, with its international partners."
The party also promised to raise the top rate of income tax in Germany to 49 percent for people earning more than €100,000 annually or married couples earning more than €200,000 between them.
Currently, people earning more than €52,882 pay a rate of 42 percent income tax. There is also a so-called "rich tax" affecting those who earn more than €250,000, who pay a rate of 45 percent.
At the European level, the SPD called for a "common economic government" and for the European Commission to be elected by the European Parliament.
"The EU should only legislate what is reasonable at that level. Everything else should remain the individual responsibility of individual member states," said the manifesto.
"The SPD wants to govern because the CDU, CSU and FDP can't," concluded the manifesto, referring to Merkel's conservative Christian Democrats and her pro-business Free Democratic allies.
The manifesto must be formally adopted by a party conference next month.
A survey released on Thursday put the SPD on 26 percent with Merkel's CDU/CSU on 40 percent. But a national poll last week put social justice as the top issue for German voters.