Harriet Harman has told men in the Labour Party they should aspire to be deputy leader.
Speaking in Dublin Castle today, Ms Harman told The International Congress of Parliamentary Women's Caucuses that Labour's next leader must be a woman.
"In my party, we regard ourselves as the party for women, yet in 100 years we have never had a woman leader, it appears only men are able to rule the Labour Party.
"Next time, we have to have a woman.
"Don't get me wrong, we have many brilliant men, and I encourage their ambition, I tell them: 'You are an asset, I want to encourage you to aspire because one day, you could be deputy leader'."
Ms Harman, told the delegates from over 40 countries, that when she was first elected in 1982, the House of Commons was 97 per cent male, she went on to give birth to three children while an MP, and received death threats when she was first elected.
"When I was first an MP, I was subjected to death threats, I didn't publicise this, as I was worried my constituents would think I was too preoccupied and scared to represent their views in parliament.
"I now think that was a mistake, because its not about proving we're tough, attacks on women MPs are not just misogyny, they're anti-democratic, if a woman is elected, she is entitled to get on with her job.
"Our dear friend Jo Cox, was murdered for doing her work as an MP.
"We have to take threats seriously, it's not us being weak but voicing that this is a problem.
"There are many countries in world where there is a reemergence of misogyny, and don't expect to be popular as a woman in public life.
"You will be described as loud and aggressive when you are just doing your job.
"I mostly believe, if you're not having a row you are not doing anything, if you're popular, step up your act a bit."
Ms Harman (68) added that she believed the House of Commons must undergo changes to adapt to modern life.
"When I first got elected, men told me; 'Harriet, don't bang on about women's issues, people will think you're a one-trick pony, they'll think you're narrow and don't understand politics'.
"However, we didn't think we had to change our agenda, we wanted to change the political agenda.
"We have to reflect reality, women are now in parliament, and we have to change how parliament works.
"Younger women and women having babies, we need things like proxy voting for new mums.
"Those who voted for that woman need her vote in parliament, she should be able to assign her vote to vote on her behalf so the people she represents have their vote cast."
The first stand-alone International Congress of Parliamentary Women's Caucuses aims to bring awareness to the issue of women's representation and the concerns facing women in politics.
President of Ireland Michael D Higgins and Taoiseach Leo Varadkar both addressed delegates during the two-day event.
Other notable speakers include Catherine McGuinness, Ms Justice Mary Laffoy and Professor Mary Beard.
