Women will in effect work for free for the rest of the year because of the gender pay gap, which will take 60 years to close at the current rate of progress, campaigners say.

The Fawcett Society called for more action from the government and employers to tackle pay discrimination, job “segregation” and help women into senior posts.

Thursday has been labelled equal pay day (EPD), with the society saying the 13.9% pay gap means women are in effect working for nothing from now until the end of the year.

The Fawcett Society chief executive, Sam Smethers, said: “A root cause of the gender pay gap is that we don’t value the work done by women. As we mark EPD this year, we are focusing on the fundamental question of who and what we value and asking why it is that we don’t value women and the work they do – paid or unpaid.

“Equal value goes to the heart of the fight for pay equality, because the reality is that if it is a sector dominated by women the pay will be lower. As we look ahead to a UK outside the EU and possibly the single market, we have to guard against the risk of going backwards and losing some of the rights that women have fought for over many years.”

The society says in a report that the jobs women do are more likely to be low paid. They are also less likely to receive a bonus or progress to the highest position in their organisation.

More than 50,000 women leave their jobs early every year after having a baby or becoming pregnant, the report says. Men are being encouraged to get involved in the campaign for pay parity, especially if they have jobs in areas traditionally dominated by women.

A separate report says one in five mothers have been overlooked for a pay rise or a bonus because they have had children.

A survey of 850 mothers by The Start Up Loans Company revealed that more than a third believed they had been overlooked for promotion by spending more time at home than in the office. Two-thirds said they would have a higher paid job if they did not have children.

Another study, by Totaljobs, found that men were twice as likely as women to feel comfortable asking for a pay rise. A study of more than 4,700 employees and 145 employers showed that women typically expect to get paid a salary of £25,468, compared with £32,030 for men.

John Salt, director of Totaljobs, said: “It is disheartening that our research has revealed that, despite efforts, gender pay equality remains a prominent issue. The application and interview process is a fantastic opportunity for both men and women to negotiate a fair benefits package, including a salary that meets their expectations.

“I would urge all female candidates to aim high and feel confident in demanding the same figure as their male counterparts.”

Rebecca Hilsenrath, chief executive of the Equality and Human Rights Commission, said: “After more than 40 years since the enactment of legislation banning sex discrimination at work and in pay, it is shameful that women continue to face barriers that hold them back. We simply cannot ignore the scale of the disadvantages that working women face.

“Girls and women outperform men at every stage in education, but time after time this success is not translated into rewards at work. Women are a vital part of the workforce and any proposals to tackle the gender pay gap must be strong enough to deliver the change everyone wants to see.”