The Australian Academy of Science has 544 fellows who are recognised as the preeminent scientists in Australia and often the world. To be elected by other scientists to be a Fellow of the Academy is regarded as a great honour.

But only 80 of them are women - about 15 per cent of the total - despite a gender balance in society of half and half.

One problem for the academy, anxious to reflect society better, is that four of every five professors in university science and engineering departments are men.

The academy has decided that to get more women in as fellows, despite the dearth of them at the top of Australia's science departments, it needs to assess achievement in a different way.

The academy's president, Professor John Shine, said the reasons for the imbalance were "historical and cultural" - partly "the old thing about "women's place is in the home".

Men had an advantage in building up a track-record of research - the learned articles published - because their careers weren't interrupted.

If you took two equally good scientists who graduated at the same time, one man and one woman, a career break for the woman to bring up family meant that she lost maybe five or ten years of working time when her reputation could be built.

"If you judge them on their achievements, it's difficult for women to compete," Professor Shine, one of the world's leading molecular biologists, said.

So the task of the academy is to find a way of judging on the quality rather than quantity of publications by a candidate "relative to opportunity".

"Because of the opportunities [women] have missed, you have to take that into account."

That did not mean a lowering of standards to become a Fellow of the Australian Academy of Science, he said.

Professor Shine said it was trying to find ways of recognising achievement not by the quantity of prestigious output but by the quality, perhaps of a smaller amount.

On top of that, the science academy is making a much more determined effort to identify women achievers who might have escaped notice.

It's appointed 20 "champions of diversity" to try to get a wider mix of people into science and higher science. By diversity it means not just gender but skin colour - it wants more Aboriginal achievers and people from all over Australia.

People from the academy have been speaking to 400 leaders in universities and research institutions "to identify diverse candidates" to try to get a more diverse group of fellows at the highest level.

"If they can send us names, we can organise to work on that nomination to get the numbers of women up," he said.

He added that the dearth of women was self-perpetuating in that it meant a lack of role models for the next generation. "What that's led to is a lack of outstanding examples of women in science."

Women are increasingly going in to science and that's not always been so. Professor Shine drew on his own background. "My mother was one of five children. She was very smart but she was unable to go to university because her parents thought it was more important for her brothers to go to university."

The situation is complex, with a raft of factors from this historical bias against highly educated women, the difficulty of women competing if they take breaks from research and, on occasion, out and out discrimination in a male oriented world.

"The academy is recognising this fact and working to address it."