Candidates for the United Nations' top job will for the first time in the organisation's history hold a live debate, which will be broadcast live to audiences worldwide on television and digital platforms.

Tuesday's debate, to be carried by the Al Jazeera Media Network, will also allow UN member states and the people they represent to question the hopefuls for the secretary general post.

The current UN Secretary General, Ban Ki-moon, steps down at the end of the year after two five-year terms.

"Worldwide audiences will be able to watch, listen and follow the UN Town Hall Debate outlining candidates’ visions on the future impact of the UN on the lives of seven billion people in the countries it represents," said Abdulla Al Najjar, Al Jazeera's executive director of Global Brand and Communications.

"The candidates for this crucial role will discuss the issues that are having devastating effects around the world, from civil wars and terrorism to refugees fleeing their homes, catastrophic climate change, and ecological disasters, among many others."

Former New Zealand prime minister Helen Clark, former Portugal Prime Minister Antonio Guterres, former Serbian Foreign Minister Vuk Jeremic and former Slovenian President Danilo Turk are among the leading candidates.

"In the past, UN Secretary-Generals have been chosen behind closed doors," said Dan Thomas, Communications Director and Spokesperson for the President of the UN General Assembly.

"This time, the President of the General Assembly Mogens Lykketoft wants to ensure all UN member states and the entire world have a chance to know who the candidates are, what their vision is and see how they perform. This live Townhall will help engage people everywhere in the UN's critical mission and the need for a really great Secretary-General,"

Viewers will be able to watch the debate on TV, Facebook Live, YouTube, and aljazeera.com.

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Have something that you want to ask the Secretary General candidates?

Visit the UN NGLS website to learn how your questions can be used, and view the full list of candidates here.

Then Tweet your questions with the hashtags #AJUNdebate and #UNSGcandidates.