Mr Steinmeier said his party would create four million jobs by 2020
German Vice-Chancellor Frank-Walter Steinmeier has outlined his party's election manifesto, vowing to bring full employment to Germany.
The leader of the centre-left Social Democrats (SPD) is set to challenge Chancellor Angela Merkel in the country's 27 September polls.
The economic crisis is a key campaign issue and Mr Steinmeier said his party would create four million jobs by 2020.
Critics say the plan lacks focus and is unrealistic in recession-hit Germany.
Recent polls suggest the SPD is trailing Mrs Merkel's conservative bloc by as much as 10 points.
"We need to finally move beyond all this crisis talk and develop a clear outlook for the next decade," Mr Steinmeier told reporters ahead of the manifesto's launch on Monday.
"Particularly amid this crisis, it is essential to say that we have the potential to create these four million jobs."
Recent German jobs figures suggest nearly 3.5 million people are unemployed in Germany - Europe's largest economy - and economists say that figure could rise by as much as one million in the next year.
According to the German weekly newspaper Der Spiegel, the SPD's 67-page manifesto - entitled Plan for Germany - says environmentally friendly schemes such as the building of electric cars would employ two million Germans.
Another million would be employed in the health industry to cater for the country's ageing population, while boosting creative industries would create a further million jobs.
Economy Minister Karl-Theodor zu Guttenberg, from Mrs Merkel's conservative CDU-CSU alliance, criticised the pledges, saying they were short of detail.
"People are sick of being bombarded with pledges during election campaigns," Mr Guttenberg was quoted as saying by AFP news agency. "They are right to expect specific proposals. There are very few of those in the SPD plan."
The centre-left SPD has been the junior partner in Mrs Merkel's coalition for the past four years.
But when the German chancellor launched her party's election manifesto in June, she voiced hopes her party would do well enough to allow it to jettison its coalition partner.
Mrs Merkel's campaign is centred on a pledge to cut taxes, which the SPD has condemned as a "tax gift" giveaway.
Mrs Merkel hopes to get enough votes to replace the SPD with the pro-market Free Democrats (FDP).
Despite the ongoing economic crisis, Mrs Merkel remains popular in Germany, but opinion polls have suggested the CDU and FDP may not be able to garner enough votes to work together.