Helen Clark believes she was unsuccessful in her bid to become Secretary General of the United Nations (UN) because the system is rigged against women.
The former Prime Minister of New Zealand made the comments while promoting My Year With Helen, a documentary by Gaylene Preston, which is returning to cinemas soon.
Ms Clark said that while she was proud of all her achievements, including those at the UN, sexism in the organisation meant she never had a chance of landing the top job, regardless of how qualified she was.
"Well it wasn't a fair fight," she said.
"The extent to which it was loaded was something we could never have anticipated... I had been a long-term leader in New Zealand, quite a successful Prime Minister. I was the third-highest person at the UN - if I couldn't have a credible bid at it, who on earth could?"
Ms Clark said the UN would lose credibility if it wasn't led by a woman soon.
"If the 10th Secretary General, elected in effect by the five permanent members, is a man - I think the UN will be a laughing stock," she said.
"What I think has been positive is [the documentary film] is making a lot of women very angry - and it's actually making a lot of men pretty angry as well. People are angry.
"[To them] I say: don't get mad, get organised."
Ms Clark expressed frustration with recent controversies around current Labour leader Jacinda Ardern and questions she faced in the media.
"It's time for women to get really mad about this sort of stuff," Ms Clark said.
"The humiliating thing for New Zealand is that this idiotic questioning went right through the global media. It made New Zealand look like a country of dorks.
"We've been through a post-feminist era and a lot of younger women think the battle is won. Clearly it is not won and that's the message of that film."
My Year With Helen is playing at the 2017 New Zealand International Film Festival and returning to cinemas on August 31.