Of the 10,450 organisations who had reported their figures by Friday, 78 per cent (8,128) showed a gender pay gap in favour of men.
Only 14 per cent (1,427) showed a gap in favour of women, with the rest reporting no difference.
Some 9,339 employers have so far reported comparable figures for both 2017/18 and 2018/19, of which 4,140 (44 per cent) showed a gap increasing in favour of men, and 742 (8 per cent) showed no change.
High-profile organisations that reported some of the largest pay gaps for 2018/19 include the airline Ryanair (64.4 per cent), the health provider Intrahealth (57.4 per cent) and Sheffield United football club (48.2 per cent).
Employers whose gender pay gap increased in size year-on-year include Huddersfield Town football club (up from 20.9 per cent to 39.6 per cent), the Department for Digital, Culture, Media and Sport (up from 8.2 per cent to 22.9 per cent) and Dyfed-Powys Police (from 8 per cent to 22.5 per cent).
The Government Equalities Office estimated around half of private sector employers have put in place an action plan to tackle their pay gap.
Of 8,424 private firms reporting their data, 3,387 saw their pay gap worsen, 3,736 saw it improve and 645 reported no change, the Government said.
All employers with more than 250 staff had until midnight last night to report gender pay details or face legal action, including fines.
The Equalities and Human Rights Commission said it will now be contacting firms which had not supplied information.
The Chartered Institute of Personnel and Development (CIPD) said there were “marked differences” between regions, with the median gender gap lowest in Scotland at 5.7 per cent and highest in the south-east and south-west - both 11 per cent.
Chief executive Peter Cheese said: “It’s disappointing that many employers are still not providing a narrative or action plan.
“Organisations that simply provide their numbers are failing to meet the increasing appetite and expectation for transparency amongst all stakeholders, including employees, investors, and regulators.”
TUC general secretary Frances O’Grady said: “Big employers clearly aren’t doing enough to tackle the root causes of pay inequality and working women are paying the price.
“Government needs to crank up the pressure. Companies shouldn’t just be made to publish their gender pay gaps, they should be legally required to explain how they’ll close them, and bosses who flout the law should be fined.”
Carolyn Fairbairn, director general of the CBI, said businesses cannot close the gap by themselves, adding: “Many of the causes lie outside the workplace including a lack of affordable, high-quality childcare and better careers advice.
“Companies and Government working together remains the best way to deliver the long-term, lasting change that’s needed.”
Minister for Women and Equalities, Penny Mordaunt, said: “Actions to tackle the gender pay gap are good for business. That’s why we have produced support to help employers close their gaps.
“We recognise that in order to close the gap entirely we still need a much wider cultural change, that is why we have introduced a range of initiatives to tackle the drivers of the gap, including shared parental leave and spending around £6 billion on childcare support.”