UNITED NATIONS - UN Secretary-General Ban Ki-moon, whose term will conclude at the end of 2016, said Wednesday that he hoped member states will expedite their process to select the next UN chief as soon as possible in a transparent manner.

At his end-of-year press conference, Ban said "member states have been actively discussing this issue, how to make selection process of my successor more transparent," while hailing a joint letter by presidents of the General Assembly and the Security Council as "a good initiative" to that end.

The letter, signed by President of the 70th General Assembly Mogens Lykketoft and Samantha Power of the United States, who serves as the Security Council president for this month, set in motion the process of selecting the next UN secretary-general.

The letter, which was circulated to member states on Tuesday, invited them to present candidates with "proven leadership and managerial abilities, extensive experience in international relations and strong diplomatic, communication and multilingual skills."

The move is seen as a showcase of the principles of transparency and inclusiveness, which has been widely asked to guide the selection process by UN member states in a General Assembly resolution adopted in September. The resolution also promised to ensure that both gender and geographical balance are given proper consideration.

In addition, a working group report which helped inform the resolution stated that member states had called for more opportunities to interact with candidates in informal meetings and for selection criteria to be set out.

In response to that request, the two presidents noted in the letter that they would offer candidates opportunities for informal dialogues or meetings with the members of their respective bodies, and "any such interaction will be without prejudice to those who do not participate."

"These can take place before the council begins its selection by the end of July 2016 and may continue throughout the process of selection," said the letter.

According to Article 97 of the UN Charter, the UN secretary-general shall be appointed by the General Assembly upon the recommendation of the Security Council. "He shall be the chief administrative officer of the Organization."

In practice, the General Assembly is given the opportunity to approve a single candidate put forward by the 15-member Security Council. The candidate has to gain support from all the five permanent members of the Security Council -- Britain, China, France, Russia and the United States.

So far, two candidates have been nominated: Vesna Pusic, Croatia's female foreign minister, and Srgjan Kerim of Macedonia, a former UN General Assembly president, said Lykketoft on Tuesday, while calling for more candidates to be presented.

In the past 70 years, there have been eight UN secretaries-general, from South Korea, Ghana, Egypt, Peru, Austria, Myanmar, Sweden and Norway, all being male.

There has been a widespread calls, both inside and outside the world body, for a female UN secretary-general.

Earlier this year, the nongovernmental organization Equity Now issued a call for a female secretary-general. It listed the names of dozens of women it thought qualified for the job in addition to presidents, prime ministers, chancellors, ministers, heads of international organizations and UN under-secretary-generals.

The joint letter of the two UN councils, echoing to that point, said "convinced of the need to guarantee equal opportunities for women and men in gaining access to senior decision-making positions, member states are encouraged to consider presenting women, as well as men, as candidates for the position of secretary-general."

"We note the regional diversity in the selection of previous secretaries-general," it added.