Some diplomats and observers, including Britain's UN ambassador Matthew Rycroft, believe the world body needs someone with the qualities of a military commander to do the job.

"The job is a big one. We want not a secretary but a general. And I hope this transparency that we brought in will increase the chance of doing that."

Under the UN Charter, the 15-member Security Council has the final say in who will be the next UN chief.

But there have been growing calls to overhaul this rule. One rationale is that a more transparent and inclusive appointment process can help to pick a more capable candidate to deal with this rapidly changing world.

Hence the informal meetings with the candidates at the General Assembly this week.

联合国需要一个怎样的领导人?

Calling the process a potential game changer, current president of the General Assembly, Mogens Lykketoft, is an active promoter of the new procedure.

But he says the secretary-or-general debate is over simplified. He argues a qualified candidate should bear the qualities of both types.

"It is in order to increase the knowledge about the candidates in order to find the best candidate, the best person that can be the moral authority of the global community, a person with political skills, diplomatic skills, a person that will also be able to lead the reorganization of this organization."

There have also been many calls for the next holder of the position to be a woman. Both the president of the General Assembly and current UN chief Ban Ki-moon and some major countries including the US and the UK support this idea.

Political science lecturer with The City College of New York and Columbia University Jean Krasno is also a UN-issues observer. She says it is not just about gender equality. She believes a female UN chief would bring some unique perspectives to dealing with the world's problems.

"When we look at the crises around the world - whether it's civil wars in Africa and the Middle East or the massive migration into Europe - it's often women that bear the brunt of this. They need a voice, and what better way to give women a voice than have the top post at the U.N. be a woman?"

All four female candidates have strong resumes. Both UNESCO boss Irina Bokova and chief of the UN Development Program and former New Zealand Prime Minister, Helen Clark, were reelected during their terms.

Man or women, Clark says the fundamental question remains whether a candidate has the skills the post requires.

"When you look at the photo gallery, there is no women's name there that has been the secretary general. So has the time come? Of course it has come. But the key thing is that the person must have the skills for the job."

Some analysts say, regardless of the audition process, pressure for gender equality and the traditional geographic rotation when choosing a new head, the basic fact remains - the outcome of the contest will be decided by the Security Council, based on each candidate's ability to do the job.

For CRI, I'm Su Yi in New York.