A cross-party group of female MPs has launched a campaign to force employers to publish details of their gender pay gap as the first step to achieving pay equality.

The #PayMeToo campaign aims to support women in lobbying their bosses to end gender pay discrepancies in their companies.

It comes days before a legal deadline for all companies with more than 250 employees to publish details of their gender pay gap.

The online #PayMeToo campaign will seek to replicate the success of the #MeToo hashtag in highlighting the prevalence of sexual harassment and assault.

The campaign is being led by Labour MP Stella Creasy and is backed by female MPs from all the other main political parties.

It encourages women to speak to their colleagues and bosses about the need to tackle gender pay gaps, and advises that they join a trade union and set up a women’s network at work.

The MPs are also asking women to take part in a survey, which they say will “help inform our work tackling the gender pay gap and fighting for equality in Britain”.

Ms Creasy told The Guardian: “If we are serious about tackling the gender pay gap then we have to do more than publish data – we have to show we’re watching what happens next.

“Women are already telling us that they are being told not to ask difficult questions about this for fear of affecting their careers and we want to be clear that trying to silence employees isn’t the right response.

“Every woman has her own story of experiencing pay discrimination in her career, including me – now they need to know they have MPs ready to listen to them and act.”

Sending a warning to employers who are not doing enough to try to achieve pay equality, she added: “If you have a gender pay gap you should expect to be challenged to address it and held to account if you try to stop your staff speaking up, whether by trade unions, women’s networks or parliament.”

The campaign is backed by Labour MPs Jess Phillips and Lucy Powell; Conservative MP Nicky Morgan; the Liberal Democrats’ Jo Swinson, Christine Jardine and Layla Moran; SNP MP Hannah Bardell and Plaid Cymru’s Liz Saville Roberts.

Ms Morgan, who chairs the Treasury Select Committee, said: “Getting the figures published is just the start – now is the time to start challenging employers to take action to eliminate the gap.”

Private companies have until midnight on 4 April to report their pay gaps or else face hefty fines from the Equality and Human Rights Commission.

Firms with fewer employees are not legally obliged to publish the details but are being strongly encouraged to do so, including by many employees, to ensure they are paying female staff fairly.

Last week, data published by public sector organisations revealed almost nine in 10 bodies pay male staff more than women. The average pay gap across the public sector was 14 per cent.