The Australian Council of Superannuation Investors' (ACSI) is calling on companies to diversify the age level on boards, which it says can go hand-in-hand with appointing more female candidates, who are now an average of six years younger than their male counterparts.
The ACSI research into board composition over the past 15 years showed a three-year rise in the average age of ASX100 directors since 2001. While 81 per cent of men on boards are in the 60-69 year and 70+ age brackets, only 40 per cent of women are in the same age range.
"The still large cohort of long-serving male directors over 70 years of age, 14 per cent of men compared to two per cent of women, is helping drive the average up," ACSI chief executive, Louise Davidson, said.
"Two out of every three male directors are over 60."
Davidson said a higher candidature of female directors would help drive down the national average age, while companies would also benefit from a female perspective.
The study showed women were on average, aged 57.9 when appointed to boards, compared to men who had a median age of 63.5 at the time of their first tenure.
"Gender diversity is a no-brainer for boards with a clear vision of their company's future, because it is more likely to bring in a wider range of skills, experiences and ideas," Davidson said.
"Boards ought to be ensuring they have sufficient diversity on a number of fronts — or risk falling behind their competitors."
The ACSI research said that while women have brought generational change to boardrooms since the turn of the century, there were still lower numbers of female board members than anticipated in the wake of the recent endorsement to reject male board members for organisations with no female directors.
In 2015, 21 per cent of ASX200 directorships were held by women, with the ACSI target for the end of next year set at 30 per cent.