At a private working lunch for the five most powerful members of the United Nations Security Council, the conversation turned to the question of the next UN secretary-general.

A European ambassador reminded colleagues of a General Assembly resolution nearly as old as the 70-year organization itself, a guiding document for a selection process for UN chief that has remained secretive and almost completely male. The January 1946 resolution says a "man of eminence and high attainment" should hold the post.

Perhaps, the ambassador suggested, some might want to add the words "or a woman."

No doubt. Just three female candidates have been included in past closed-door votes and straw polls that the Security Council has used to make its choice for decades, but now two campaigns are launching to make sure the next "Your excellency" is a she.

"There have been eight men and no women. To me, it's time," said Jean Krasno, a lecturer at Yale who leads the new Campaign to Elect a Woman Secretary-General.

Secretary-General Ban Ki-moon will remain in office through Dec. 31, 2016, but the talk about his successor has already started, especially among UN watchers who've gone as far as scrutinizing the handwriting on paper ballots after Security Council straw polls. Ban's successor is expected to be chosen late next year, though there is no official date.

On Sunday, the campaign will launch WomanSG.org to feature around a dozen women it says are outstanding possible candidates with political experience. Every few weeks, another group of possible candidates will be posted online.

Next month, the international women's rights group Equality Now will launch a similar Time for a Woman campaign while urging the public to pressure the UN and member states to make "gender a serious consideration for the first time," said the group's legal adviser, Antonia Kirkland.

Women that they're pointing out include Helen Clark, former New Zealand prime minister and the head of the UN Development Program; Bulgarian European commissioner Kristalina Georgieva; Lithuanian President Dalia Grybauskaite; Chilean President Michelle Bachelet and Danish Prime Minister Helle Thorning-Schmidt.

"And obviously, you could have some sort of dream thoughts around (German Chancellor) Angela Merkel," said Laura Liswood, the secretary-general of the Council of Women World Leaders, a collection of 53 current and former female heads of state that's not part of either campaign.

Another name floating around is International Monetary Fund managing director Christine Lagarde, though as a Frenchwoman, she is likely a long shot. Candidates from the five permanent council members' countries -- the United States, Britain, France, Russia and China -- are by tradition not considered.

The topic is a popular one as women's organizations from around the world assemble at the UN for this week's meeting of the Commission on the Status of Women and side events featuring Hillary Rodham Clinton and Melinda Gates.

The world currently has fewer than 20 female heads of state and government, and women make up about a quarter of posts in the UN Secretariat's most senior levels. A female secretary-general "will be a cherry on top," the head of the UN agency promoting equality for women, Phumzile Mlambo-Ngcuka, told reporters Friday.

The race for secretary-general, just as the one for U.S president, is long on both time and speculation, as shown by last week's lunch, recounted by a UN source with direct knowledge of the event who spoke on condition of anonymity to discuss the private conversation.

Tradition says each region, such as Africa or Asia, gets its turn at having someone in the top post, though the UN Charter says nothing about it. This time would be the turn of eastern Europe, which has never had anyone in the job. The female head of the UN cultural agency, UNESCO Director-General Irina Bokova, is already a favourite in speculation with a nomination from her native Bulgaria.

But along with the calls for a woman in charge are high-profile demands to shake up the selection process for secretary-general altogether, which could allow for a larger pool of female candidates from around the world.

The campaign 1 for 7 Billion, which launched last year with the support of dozens of NGOs like Amnesty International, takes up the frustrations of many of the 193 UN member states who say they have little voice in picking a secretary-general. The Security Council, dominated by its five permanent members and their veto power, essentially emerges and hands a single candidate to the General Assembly of all member states for its approval.

Enough, the campaign says. It wants more transparency and public input for the best candidate, "irrespective of his or her country of origin." While 1 for 7 Billion doesn't demand a female secretary-general, it points out that a woman has never held the job.

In February, former UN Secretary-General Kofi Annan joined with one of the three women ever voted on by the Security Council in its deliberations for UN chief, calling for a stronger United Nations. Annan and former Norwegian Prime Minister Gro Harlem Brundtland said the council should make the secretary-general selection process more open and thorough -- and in time for picking Ban's successor.

"After eight 'he's' it's surely time for a 'she,"' they wrote in an opinion piece for The New York Times.