The gender pay gap in Australia has widened over the last decade with men earning 20 per cent more than women.

Women are paid less even when working in the same role as men in top accounting firms across the country, workforce diversity special Conrad Liveris told ABC.

He said PriceWaterHouse Coopers, EY and Deloiette pay women between 1 and 5 per cent less than men for the same jobs.

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Men earn an average of 20 per cent more than women in Australia in some sectors of the workforce (stock image)

'Even at their highest level, at the partnership level, they were finding about a 5 per cent gender pay gap in a like-for-like basis,' Mr Liveris told ABC.

Deloitte said the reason for the pay disparity in its most senior job is due to the range of experience of staff 'and the greater prevalence of males at the upper end of this range'.

'We have eliminated any gender pay gaps at this level on a like for like experience basis,' the accounting firm told ABC.

Daily Mail Australia has contacted the firm.

Mr Liveris said the big accounting firms were 'using their influence in a really positive way'.

Mr Liveris said the gender wage gap for total full-time earnings was an average of about 20 per cent.

He said the healthcare sector was among the worst offenders with a gender pay gap of almost $500 per week.

Official weekly earnings figures show the gender pay gap has risen over the last 10 years from about 15 per cent in 2004.

It reached a record high in 2015 before falling slightly this year.

Some women are even paid less than men in the same roles at the same companies (stock image)

The Australian Council of Trade Unions (ACTU) said the wage gap remained 'stubbornly high' despite being the focus of increasing public interest.

ACTU said the average weekly ordinary time earnings (AWOTE) was 16.1 per cent less than men, or $260 a week.

Average earnings are lowest in the retail and food sectors, ACTU said, 'demonstrating yet again the critical importance of penalty rates for workers in these industries, many of whom are women'.

Average superannuation balances for women at retirement are 52.8 per cent less than those for men, government figures recently released through the Workplace Gender Equality Agency said.

ACTU said Australia had dropped from being 15th on the Global Gender Gap Index in 2006 to 36th in 2015.