Having now concluded that self-regulation has failed, Ms. Reding has set her sights on legislation that could, if enacted, drastically speed up a revolution in the position of women in the workplace that began many decades ago but has so far failed to deliver genuine equality in many areas of business.

In the announcement to be made Monday, Ms. Reding will call for a new round of consultations with governments, trade unions, companies and civil groups. The move comes a year after she called on companies to take voluntary steps to increase the representation of women on boards to 30 percent by 2015 and to 40 percent by 2020, by replacing departing male directors.

In the end, only 24 companies signed up to that voluntary measure — “a disappointment,” she said.

Yet that poor showing has handed Ms. Reding — who has gained stature by successfully lowering the cost of cellphone calls and confronting government leaders over the mistreatment of minority groups — an opportunity to prepare the ground for more sweeping proposals.

Ms. Reding said that the severe economic downturn in Europe that has pressured companies to focus on their bottom lines was not responsible for the failure of her voluntary initiative. “It is really a question of society,” she said.

As of January, only 3.2 percent of the presidents and chairmen of large companies in the European Union were women, and women occupied only 13.7 percent of the seats on the boards of large companies, according to a report by her department of the European Commission to be issued on Monday.