The pioneering bureaucrat defied such attitudes to make a rapid ascent as the first woman to lead a Commonwealth department in 1985, aged 39. On Saturday, she will be appointed a companion of the Order of Australia for her contribution to the public service.

Ms Williams met resistance on her way to the historic appointment heading the Education Department.

Women were thin on the ground and awareness of gender equity was in short supply when she worked at Treasury and the newly-created Department of Finance in the 1970s. It was not unusual for women to be asked at job interviews whether they were likely to get married and have children.

Before the then-Finance Department secretary, the late Sir William Cole, appointed her its first female branch leader, a prominent division head said it would happen over his dead body. As Sir William later observed, the man didn't die.

Her decision to take six months' maternity leave as Education Department secretary in 1987 drew reaction from both women's groups and the senior bureaucracy. The episode is only three decades removed from last year's milestone for the public service, when departmental secretaries reached a 50:50 gender balance.

Ms Williams went on to head the departments of Human Services, Communications, Tourism and Immigration, and the public service commission, before her retirement in 2009. For 17 years she was the only female departmental secretary.

The public service today has a 59 per cent female workforce, but most senior levels remain dominated by men. Today, 45 per cent of the top-level senior executive service is made up of women. In 1983 it was 2.3 per cent and there were no female deputy secretaries, facts Ms Williams describes as disconcerting.

"Moving forward to the last decade or so, however, things have changed increasingly quickly and it was a real plus when the number of women at secretary level hit parity last year," she said.

"Unfortunately that parity isn't yet mirrored at all levels of the service but the fact that it is no longer a matter of comment when women are appointed to senior positions shows an important recognition of their skills and commitment."

Ms Williams joined the public service in 1970 looking for something to do for a year and intending a return to England, where she had previously lived for 22 years.

"Chance again sent me on a rotation to the Treasury which had immense reach before the separation from Finance in 1976. It gave me the opportunity to work on some complex policy issues and to see them in the cross-government economic context," she said.

"I was fascinated and the return to England was firmly off the agenda."

The bureaucracy then had typing pools producing typed minutes, calculator results were printed on a roll of paper, and information had to be gleaned from paper files, reports, or library research.

"In discussing the need to cope with rapid changes in technology, it's important to remember the substantial changes that the service has already faced in this area," Ms Williams said.

"Technology has given us faster and wider access to information and data, as well as the ability to manipulate that data, in a way that simply couldn’t have been predicted at that earlier stage."

Among the other major changes to the Australian Public Service she witnessed was the growing contestability of advice, both from consultants and contractors, and from much-expanded ministers' offices.

She counts education and social services as the areas of her keenest interest, but said every role she had was engaging, in both policy and administration terms. Ms Williams also mentions her work on the Hawke-era New Federalism Initiative of reform to Commonwealth-state relations, a project that didn't reach fruition.

"Even though, despite early gains, it didn’t eventually achieve what was hoped, I thoroughly enjoyed the challenge of working with the states and territories on a range of contentious cross-border program issues."

Ms Williams was appointed an officer of the Order of Australia in 1993.