One of the most powerful women in the history of the public service has called out Canberra's stubborn glass ceiling, describing the frustration of being held back in place of men.
Former Finance Department secretary Jane Halton said she was wrong in believing there were no barrier for advancement and saying "a special place in hell" exists for women who don't support other women.
Retiring in late 2016 after 33 years in the public service including 14 as a secretary, Ms Halton was at the centre of some of the most controversial political events of recent governments, including the children overboard inquiry and the introduction of tobacco plain packaging laws.
"I used to believe that there wasn't a glass ceiling, and there is," she said in a podcast interview with Labor MP Andrew Leigh.
"I very clearly know the first moment my head hit it, absolutely very, very clearly.
"I think you can see and feel the difference in workplaces where there's what I always used to say is the 40-40-20 split. That's 40 men, 40 women and the rest of the 20 doesn't matter. You need critical mass and I don't think 30 per cent is enough."
Ms Halton joined the board of ANZ last year.
A former deputy secretary of PM&C and boss of the Health Department for more than a decade, she described occasionally being forced to take her children to hastily called meetings with senior ministers.
"Frankly if it worried anyone else, I couldn't have cared less," Ms Halton said.
"I've got a reputation for being pretty robust but also calling it quite straight for what I see. The comment that was made about me as I departed by people from both sides of politics was 'you're never in any doubt about what Jane thinks'. And that's true."
A formidable presence under governments from both sides of politics, Ms Halton was the first woman to lead a central department.
"I really worked hard at bringing women up through the system. I've always liked the Madeleine Albright line that there's a special place in hell for any women who doesn't reach down and pull other women up. I still think that's the case."
With women making up 48 per cent of Finance's senior staff at the time of her retirement, Ms Halton said giving men more flexible working arrangements would help close the gender pay gap.
"Certainly when I became relatively senior, there weren't a lot of women around. I was very lucky that I did work for a lot of senior women so I had a few people to watch but when I was coming up the ranks, there were no female secretaries.
"In those days you didn't even see a secretary very much so the notion of how the big leadership tasks were tackled from either gender, let alone from the female perspective, was just not something you could even watch to learn from."