According to the plan, large companies would have the next two years to voluntarily increase the number of women in leadership positions. But if numbers don't triple by 2013, then a law enforcing the responsibility to do so would be enforced, Schröder explained.
In the past, voluntary commitments by companies have made progress, but not enough, she said.
“Now we need more liability, but without setting a uniform quota by the state,” she told daily Passauer Neue Presse.
The conservative minister also welcomed a suggestion by Economy Minister Rainer Brüderle to form a pact with economic associations to improve the situation for women in companies.
“It goes right along with my graduated plan,” she said.
On Wednesday, Chancellor Angela Merkel had ruled out a mandatory quota, effectively ending an internal debate within her party on the subject.
Through her spokesman Steffen Seibert, Merkel said there would be “no legally obligatory quota,” because such a regulation was unenforceable. However she put the business community on notice that it must work harder to raise the number of women in top jobs.
A recent survey by the German Institute for Economic Research (DIW), found that just 2.2 percent of leadership positions at Germany's top 100 companies are women - only 11 out of 490.
Merkel's conservative Christian Democratic Union (CDU) party had been locked in a debate on the matter this week after Labour Minister Ursula von der Leyen and Family and Social Affairs Minister Kristina Schröder locked horns publicly on the issue of a mandatory quota.
Von der Leyen favoured a mandatory quota of 30 percent women on company boards and in executive positions. Schröder said she was also in favour of a quota but insisted it must be voluntary.