The majority of medium and large companies pay higher wage rates to men than to women, according to the latest government figures.
The disparity, known as the the gender pay gap, reflects the different average hourly salaries earned by men and women.
The government data showed 74% of firms pay higher rates to their male staff.
Just 15% of businesses with more than 250 employees pay more to women.
As many as 11% of firms said there is no difference between the rates paid to either gender.