Women are underrepresented in managerial roles in the Netherlands because they are more likely to work part time, the government’s socio-cultural advisory body SCP says in a new report.

Only when people work at least 28 hours a week, are they likely to move into middle management jobs, the SCP researchers said.

Some 74% of Dutch women do not work the standard 40-hour week – on average they work just 28 hours.

‘If you want to reach the top, then you have to work full time and more,’ researcher Ans Merens told the Volkskrant. The SCP research shows senior managers tend to work at least 50 hours a week.

Efforts over the past 10 years have boosted the percentage of women in top private sector jobs from 4% to around 15%, still well below the target of 30%. And last year MPs voted in favour of bringing in quotas for female representation on supervisory boards.

That vote followed a call for compulsory quotas by the SER, which said this would make company leadership a fairer reflection of society. The VNO NCW business lobby group also came out in support of a quota for the first time.

Economics professor Janneke Plantenga told the Volkskrant that the Dutch system is based on women working part time. ‘School hours, childcare, leisure facilities, it is very difficult as an individual woman to break out of this,’ she said.

Plantenga suggests that working hours become a part of the annual appraisals that most workers have, so that bosses can continually raise the issue with young women.

‘If you are 32, with two young children, then a 40-hour week might be complicated, but children grow up,’ she said. ‘Then you should be able to break out.’