The pay gap between male and female accountants in New Zealand is getting worse.

The pay difference between male and female chartered accountants in New Zealand has blown out to an "unacceptable" $45,000, the greatest discrepancy in five years.

The 2015 Remuneration Survey by Chartered Accountants Australia and New Zealand (Chartered Accountants ANZ) showed male chartered accountants in New Zealand earned an average of $45,573 more than females, the widest pay gap since 2010.

This result was based on a 29 per cent response rate from New Zealand members of the organisation.

Chief executive of Chartered Accountants ANZ Lee White said the gap starts early and compounds significantly over the years.

The data showed the pay gap emerges within five years of starting in the industry, kicking in strongly after eight years and peaking between men and women who have 21 years or more experience.

"The gap is getting worse instead of improving like in other sectors and further research we've done shows that factors such as work experience and career breaks don't impact this result," White said.

"Our research shows that around 20 per cent of the gap can be attributed to gender only. That is unacceptable."

Gender also had a greater role in the pay difference between older accountants, with men aged 50 years or older earning on average $55,000 more than women in the same age category.

White said this partly reflected the fact that older men were more likely to hold senior positions.

Staples Rodway associate director Tracey Hickman said in her experience there were more men than women in senior positions.

But with more women entering the profession and progressing up the ranks, the balance would improve and the pay discrepancies reduce, Hickman said.

She said Staples Rodway made no differentiation in pay based on gender and she had never experienced gender-based pay inequality in her 30-year accounting career.

"I really don't believe there's institutional gender bias. If you had exactly the same job and you had a man and a woman applying for it, I'd be surprised if a woman was offered a lower salary just because she was a woman," she said.

Across sectors, the gender pay gap is widest among corporate chartered accountants, followed by public practice and the public sector.

Chartered Accountants ANZ has launched a diversity project that will include a mentoring programme for young female chartered accountants.

It will help them to recognise their value and to negotiate remuneration successfully.

The organisation was also sponsoring the diversity category at this year's Women of Influence programmes in New Zealand and Australia.

Overall, pay increases in the accounting industry have been modest since 2013 with the biggest increases going to chief executives, business owners or directors and managing directors.