Only a third (31%) of high earners under 30 are women, according to research from law firm Clyde & Co.
Data obtained directly from HMRC revealed that women represent 31% of all 192,000 higher rate tax payers aged 20 to 29. Women over 60 accounted for just 23% of all higher rate tax payers in this age group in the last financial year.
Gina Wilson, an employment partner at Clyde & Co, expressed concern that the pay gap remains apparent across all age groups. "Until there is a far more even split between the genders there is clearly still work to be done," she said.
"For the over-60s the problem is perhaps less surprising," she added. "Women find it harder to get into those higher-paying senior roles, especially when they have had to deal with maternity leave and childcare responsibilities when returning to work.
"However, those under 30 should be freer of that conscious or unconscious bias and as able to attain high-paying jobs as their male counterparts. The fact that they're not is very concerning."
To comply with upcoming gender pay reporting legislation Clyde & Co recommends that on 5 April companies should take a snapshot of their pay data and review it, considering how they would report it following the requirements of the rules, and consider whether to report more than the bare minimum.
The firm also suggests that employers tackle the influence of unconscious bias in the workplace with effective training for recruiters and managers.
Clyde & Co's report coincides with research from Workingmums.co.uk, which found that the majority of employers believe gender pay audits will be positive for business.
The survey showed 86% of employers were positive about the audits (which come into effect in April). The approval rating was 90% among employers with more than 1,000 employees and 100% of those with between 250 and 500 employees.
Gillian Nissim, founder of Workingmums.co.uk, said employers understand the reporting requirements are part of a "positive push".
"We hope that employers will take the opportunity to contextualise their data so that we can have an honest discussion about the barriers to greater workplace equality," she added.
Virgin Media's chief people officer Catherine Lynch told HR magazine her business is aiming for a 50/50 gender split among senior leaders by 2025.
“Organisations perform better when teams have a good gender balance, with women earning as much as men,” she said. “Employers can address the underlying causes of gender inequality in the workforce through a range of policies; including family-friendly working, proactively hiring more women at senior levels, and investing in unconscious bias education."