At least 10 senior women at the BBC are working with lawyers about the gender pay gap at the corporation and could take legal action if talks with the broadcaster fail to resolve the issue.

The women are being advised by the City law firm Mishcon de Reya but other law firms are also understood to be working with BBC employees about pay.

Those talking to law firms include presenters whose names were included in the list of top earners published by the BBC. Mishcon is helping them to establish whether the BBC has failed to pay people equally for doing the same job.

Legal action could potentially take place through an employment tribunal on sex discrimination or a high court case. There is an urgency to the talks between the BBC and female staff because equal pay claims have to be lodged in the employment tribunal within six months of the discrimination. The BBC’s pay list was published on 19 July, meaning the corporation effectively has until mid-January to resolve disputes.

The pay list revealed that just a third of its highest paid on-air stars were women and the top seven were all men. This led to more than 40 of the BBC’s highest-profile female presenters, including Clare Balding, Fiona Bruce and Emily Maitlis, to publicly call for the BBC to ensure equal pay for equal jobs.

Some BBC employees are understood to have been frustrated by a series of reviews the corporation published on pay this month. The reports stated that men were being paid 9.3% more than women at the BBC on average – the UK average is 18.1% – and concluded there is “no systemic discrimination against women” at the corporation.

The reviews did not include the vast majority of on-air presenters, editors and senior managers. They also found there was a lack of women in senior roles and that in almost one in 10 occasions where there was substantial difference in pay between men and women doing similar jobs, there was no clear reason for the disparity other than gender.

Jennifer Millins, a parter in the employment department at Mishcon, said: “The figures from the BBC highlight the need for businesses across all sectors to seriously consider their diversity and makeup. The reputational fallout of any significant pay gaps is likely to be what costs businesses most dearly.”

The BBC has pledged to publish a report on the pay of on-air presenters later this year. It has said it is taking equal pay seriously, but also that the issue is complex.

Tony Hall, the BBC director general, said this month: “Fairness in pay is vital. We have pledged to close the gender pay gap by 2020 and have targets for equality and diversity on our airwaves. We have done a lot already, but we have more to do.”