The median taxable income for female judges in 2014-15 was $372,985, compared with $371,470 for male judges - a gap favouring women by 0.4 per cent. Median taxable income means half of workers earn more than this amount after deductions, and half earn less.

The gap favours men in every other top-earning occupation included in the analysis, by between 3.4 per cent for magistrates and 75.6 per cent for pathologists.

The analysis defines top-earning jobs as a median taxable income above $180,000 - the threshold for the top tax bracket - and excludes occupations with fewer than 20 female workers, 20 male workers or fewer than 100 workers overall.

The figures are not adjusted for hours worked, experience or seniority.

The chart below compares median incomes for men and women in more than 1000 occupations reported to the Australian Tax Office.

Each circle represents a job. Yellow means the pay gap favours women; blue means it favours men. The size of the circle shows the share of men in an occupation: the larger the circle, the more men dominate that occupation. The quadrants divide jobs into those with median incomes above and below $180,000. The top of the chart shows the highest paid jobs for men, the right side of the chart shows highest paid jobs for women.

High-paying ... but only for men

Four trends stand out. First, there is no such thing as a job where women are taking home large pay packets but men are not. (We know this because there are no circles in the bottom right quadrant of the plot.) On the other hand, the reverse is true for around 20 jobs in which the median income is above $180,000 for men but not women. (These are in the top left of the chart.)

Second, only one in three (11 of 31) of Australia's highest-earning jobs are lucrative for both men and women. Most are top-earning for men only. Of the 11 jobs where both men and women earn median taxable incomes above $180,000, two are in law (judge and magistrate); the remaining nine are medical specialties, such as neurologist or gastroenterologist.

Marian Baird, Chair of Work and Organisational Studies and Professor of Gender and Employment Relations at the University of Sydney Business School, said the narrow gender income gap for judges and magistrates was most likely because remuneration in these occupations was set by tribunals, rather than the market.

"In occupations where a third party or a centralised system sets the pay, there's always a smaller pay gap," Professor Baird said.

"The more you deregulate a labour market the larger the gap becomes - and that's not just between men and women. It's between high income and low income earners as well."

Jobs favouring women pay far less

The third stark trend is that the median income gap favours women in the worst-paid occupations. (This is shown by the way the yellow circles cluster in the bottom left of the chart above.) Here's the same chart but this time only showing jobs with median incomes below $100,000. Most of the yellow circles have median incomes below $50,000.

The occupations with an income gap most strongly favouring women include child care worker, general receptionist, medical receptionist, dishwasher and school teacher. The median income for women in these jobs ranged from $14,789 for school teacher (type unspecified) to $35,446 for medical receptionist.

By contrast, the median income for men in jobs where the gap most strongly favoured men was up to 11 times higher. These include pathologist, radiologist, barrister, radiation oncologist and cricketer. In these jobs, the median income for men ranged from $88,372 for cricketer to $386,485 for diagnostic and interventional radiologist.

"It's really about how we value the work that women and men do," Professor Baird said. "Certain jobs are feminised and then that work is seen as less valuable than men's work."

Working in a man's world

Fourth, the figures highlight that the overwhelming majority of Australia's highest-paid jobs (28 of 31) are male-dominated. The three exceptions are dermatologist, radiation oncologist and pathologist. These are the three yellow circles at the top of this version of the chart, which shows male-dominated jobs in blue and female-dominated jobs in yellow and orange.

"If you want to be an ophthalmologist or an anaesthetist or cardiologist, for example ... that might take 10-15 years of training, which is a much harder proposition for women than for men," said Ben Phillips, an economist and public policy analyst at the ANU Centre for Social Research and Methods.

"At some point, women come up against the baby barrier, which is not conducive to the very hard and long road into those top professions. Obviously some women do it, but it's a much easier path for a man who has a wife supporting him at home."

He said the cultural norm of women being the primary carer of young children remained deeply ingrained in Australia, despite some signs of change.

Overall, the income gap substantially favoured women (that is, exceeded 10 per cent) in just 37 or 3.4 per cent of the jobs included in the analysis. It substantially favoured men in 855 or 81.4 per cent of occupations.

Jobs where the income gap favoured women tended to be heavily dominated by one gender, whether by women (child care worker, receptionist) or men (apprentice electrician, earthmoving plant operator).

Professor Baird said women in jobs heavily stereotyped as "men's jobs" were "probably quite exceptional in their own right", and this may explain why the pay gap worked in their favour.

However, Associate Professor Phillips said it was difficult to explain without more information. "If you look at stockbroking, for example, that's very male dominated and the women would also be exceptional but they're still earning half the pay of men," he said.

Jobs with the largest income gaps

Topping the rankings for widest income difference is pathologist, with a gap of 75.6 per cent and a median income of $195,627 for men and $47,749 for women. This was followed by radiologist (diagnostic and interventional) at 74.3 per cent, with a median income of $386,485 for men and $99,509 for women; and barrister, with a gap of 72 per cent and a median income of $99,690 for men and $27,866 for women.

Professor Baird said the very low median incomes for barristers reflected two factors: the large deductions barristers could claim against their pre-tax incomes, and the systemic barriers faced by women in the profession.

"A lot of it's to do with the allocation of work: who gets the best clients, who gets to appear in the higher courts," she said.

"It's incredibly network-oriented and not very open, so continues to foster male barristers over female barristers – That really affects who gets what job and, therefore, what they earn."

Measuring economic power

Unlike the official measure of the national gender pay gap, which is based on average weekly full-time equivalent earnings, the figures do not adjust for hours worked.

However, in some ways the tax office figures present a more realistic view of the yawning gap between men's and women's earning power, Professor Baird said.

That women dominate the part-time workforce, do the bulk of work in the home and raising children, and "get stuck at the bottom end of all career ladders" all reflect wider gender discrimination in society. And ultimately, all contribute to women's scrawny pay packets.

"This is the bigger issue of the distribution of paid and unpaid work," she said.

Associate Professor Phillips said other research has shown the pay gap persists even after adjusting for factors such as more women working part time, and men tending to work longer hours and dominate senior roles.

Nevertheless, the tax office figures revealed how sharply the balance of economic power in Australia was skewed in favour of men, "regardless of whatever factors are driving that", he said.

"There's no doubt that at the end of the day, it's the money you take home, and there's a sense of economic power about that," Associate Professor Phillips said.

"It's not just a matter of calculating the wage gap. It's about the economic power that comes with money."