Annual salary increases for men and women, averaged across all levels, are level at 2.3 per cent, meaning that in real terms women are falling behind their most generously paid male counterparts, according to a study for the Chartered Management Institute.
More than 40 years after the Equal Pay Act was passed, the study shows the average salary of male managers this year was £36,119 but for women it was just £27,772 - a 30 per cent pay difference.
The National Management Salary Survey analysis also shows a more marked widening in the pay gap at director level, with men's salaries going up by 2.7 per cent while their female counterparts only got a 1.9 per cent rise.
When bonus payments are added, male directors took home £156,690 compared to £141,438 for women - a difference of more than 10 per cent.
CMI said male managers were also earning average bonuses nearly two-and-a-half times as large as those of their female counterparts. The average bonus for a female function head in Scotland stood at £8,694, while for men in the same role it was £20,887.
The study, which examines the pay of 4,100 professional workers in Scotland and 68,000 across the UK, shows the gender pay gap is widest between those aged between 45 and 60, and stands at £16,680 per year.
Petra Wilton, the CMI's head of policy said: "We are still in an outrageous position of a pay gap which is not closing at the moment. Particularly at the top level, it is widening.
"It is down to employers to act. There is still a big cultural change that needs to happen."
The findings have intensified calls by campaigners for more to be done to ensure equal pay.
Emma Ritch, executive director of Engender, said the feminist organisation was concerned about the data, and the fact that only two of the 200 companies signed up to the UK government's equal pay scheme, Think, Act, Report, were confident enough in the fairness of their own pay systems to publish their gender pay gap.
She said: "These figures make grim, if unsurprising, reading. The pay gap extends into every boardroom and cleaners' cupboard in Scotland, reducing women's lifetime and pension earnings, and limiting women's ambitions."
Anna Ritchie Allan of Close the Gap added: "These figures show that the 'motherhood penalty' continues to impact significantly on women's pay, as well as their progression and promotion prospects. A lack of flexible working in senior roles means that many women are working in jobs below their skill level.
"From our experience of working with businesses, those who incorporate an equal pay review and a job evaluation tool free from sex bias will be ensuring that their pay systems are fair. Employers who treat all their employees fairly will see their organisations become more productive and more innovative, and will reduce their costs through recruiting and retaining the best quality staff."
CMI, which compiled the data with salary specialist XpertHR, said there was good news for some female managers. Male section managers' basic salaries increased by 1.9 per cent compared to 4.2 per cent for women in the same role in Scotland. Women's annual pay awards have also edged ahead of men's in three of the five most junior job levels - an average of 2.4 per cent compared to 2.3 per cent.
Figures released earlier this year by HM Revenue & Customs showed self-employed women also earned about 40 per cent less than self-employed men in 2012.