The German parliament is to vote tomorrow on proposals to set legally binding quotas for the proportion of women on the boards of leading companies.

The draft bill coming before the lower house of the German parliament calls for 20% female representation on boards by 2018, rising to 40% five years later.

Currently, women occupy just 4% of top corporate jobs in Germany, compared with an average for OECD countries of 10%. In Sweden, France and Finland, the proportion of women on boards varies between 15% and 20%.

The new legislation is widely seen as result of political infighting between the Christian Democrats (CDU), the party of German Chancellor Angela Merkel, which leads the coalition currently running the country, and the main opposition parties. While the opposition favoured mandatory female quotas, the CDU preferred encouraging voluntary change.

However, the CDU has now adopted a manifesto commitment to impose a 30% female quota on the boards of listed firms, from 2020. Current polls suggest it will be the single largest party in the German parliament after the election in September, making it likely that this commitment will become law.