Much has been written about the need for Australian Securities Exchange (ASX)-listed companies to improve gender diversity in senior management and on their boards.

Less considered is whether enough companies are considering other critical diversity challenges at board level.

Chief among them is the ability of Australian boards to govern companies whose long-term fortunes are increasingly tied to Asia.

Institutional investors should consider when voting for board appointments at this year's annual general meetings whether the companies have enough directors with genuine Asian experience and knowledge.

They should also test whether boards have sufficient technology expertise from a risk-management perspective and to capitalise on emerging opportunities.

Companies, such as those in media and retail that are being rapidly transformed by technology, need boards that deeply understand these trends.

Yet the diversity debate has, appropriately, focused mostly on gender within executive management ranks and at board level.

There is no doubt more work is needed to lift the number of female directors at ASX 200 companies (especially in small and mid-cap listed companies) and to reduce the pay inequality gap between men and women at some large companies.

Also well known is that more diverse executive teams and boards usually make better decisions because they can consider issues from different perspectives.

There has been solid progress on gender diversity in recent years, albeit off a terribly low base.

In August 2012, 14.5 per cent of all directors in ASX 200 companies were women, up from 13.4 per cent in 2011, and 8.3 per cent in January 2010, Australian Institute of Company Directors (AICD) data shows.

But 57 of the top 200 companies by market capitalisation still do not have a female director.

Another positive trend is more ASX-listed companies are adopting the ASX Corporate Governance Principles and Recommendations on gender diversity that came into effect last year.

The ASX Corporate Governance Council recommended companies disclose in their annual report their achievement against gender objectives set by the board, and the proportion of women in senior management and wider company roles.

A KPMG study commissioned by the ASX and announced late last month found 129 of the 211 ASX-listed companies researched had established a diversity policy, and 79 had established measureable objectives for obtaining gender diversity.

A less-considered finding was that 88 per cent of companies sampled that had established a diversity policy said it covered more than gender.

Some said their definition of diversity included age, ethnicity, religious beliefs, cultural background, disability, sexual orientation, marital status, language, experience, physical ability, education and political beliefs.

Better diversity reporting is an important initiative, but institutional investors might also seek more information from ASX 200 companies on the mix of director skills and diversity.

About 70 per cent of companies sampled had a board skills matrix, but only 40 per cent disclosed the mix of skills and diversity, according to the KMPG study.

The ASX Corporate Governance Principles recommend boards have a skill matrix when selecting directors, but there is no requirement for that matrix to be published to investors.

More boards of overseas companies, especially those in Canada, are publishing skill matrices to inform shareholders of the mix of director skills and whether there are significant expertise gaps to be filled.

Institutional investors in Australia must use their judgment on whether the board is capable of governing the company to capitalise on Asian opportunities.

The AICD has lately done more work to extend its ties in Asia and is building a solid platform for diversity progress in this area.

Institutional investors would be right to more aggressively quiz boards at the next AGMs about their Asia expertise, and also whether they have sufficient skill to capitalise on technology trends that are rapidly reshaping industries.

Extending the diversity debate beyond gender is long overdue.

Tony Featherstone is a former managing editor of BRW and Shares magazines. He writes a monthly column and features for the AICD Company Director magazine.