Some of the country's most powerful and ambitious women will gather for an annual business conference today and productivity will be a topic of discussion.

The conference comes after comments made by Alasdair Thompson, the chief executive of the Employers and Manufacturers Association, who blamed the wage gap between the genders on female employees taking more sick leave than their male colleagues.

About 120 female chief executives, directors, managers and other business leaders are members of New Zealand Global Women, a branch of an international organisation that encourages and supports high-powered women in the workplace.

Founding member Dame Jenny Shipley is expected to discuss Thompson's comments today and is calling on the EMA to clarify its position on the value women bring to companies, the labour market and the wider economy.

Shipley wrote to Thompson on Thursday asking him to provide her with the statistics that back up his argument.

In the letter she said: "With the investment that employers make in women and men in this day and age, surely the issue is how to retain that talent by salary recognition and workplace flexibility, not your absurd explanation [Thompson's] why the wage differences linger.

"It is not only socialists who think that people of equal talent deserve to be paid for equal effort. While it is a matter of debate as to whether we need law to define this, I would have thought that the proposition was not only reasonable but a 'no brainer'."

Shipley said New Zealand's small economy needs "all the talent it can attract and all the effort it can deploy".

"Remuneration should be blind to gender and focused entirely on talent, productivity and the ability to assist companies to gain momentum."

The New Zealand Global Women's Forum will be held today at the Auckland University's business school.