It is to be held in the UN General Assembly hall from 6-9 p.m. Tuesday (2300 Tuesday-0200 Wednesday GMT) and available free from UNTV and Al Jazeera Media Network, producers of the broadcast, Lykketoft said at a press conference here.
"The first globally televised event where 10 of the 12 candidates for the position of the next secretary-general are able to be present," Lykketoft said.
"We all know that this is a unique process up until now of transparency," he said of the process to select a successor to Ban, who retires at the end of 2016 after two five-year terms. "This televised event open for any kind of broadcaster around the world and for social media will be yet another step forward."
"The aim we are looking for is much broader participation in the general (UN) membership and the general public of the world in the selection of the next secretary general," the president said. "This is the town hall of the United Nations."
Ten candidates who have confirmed participation, after drawing of lots, have been split into two groups to participate in discussions and answer questions, Lykketoft said.
The first group consists of Vesna Pusic of Croatia, Antonio Guterres of Portugal, Susana Malcorra of Argentina, Vuk Jeremic of Serbia and Natalia Gherman of Moldova. In the second group are Helen Clark of New Zealand, Danilo Turk of Slovenia, Christiana Figueres of Costa Rica, Igor Luksic of Montenegro and Irina Bokova Bulgaria.
Srgjan Kerim of the Former Yugoslav Republic of Macedonia and Slovakia's Miroslav Lajcak were unable to attend, Lykketoft said.
According to the UN Charter, "The secretary-general shall be appointed by the General Assembly upon the recommendation of the Security Council."
Previously, this has resulted in the council secretly choosing a single candidate for recommendation to the General Assembly.
The current selection process was opened up in the name of transparency and so far nine of the 12 candidates have been publicly interviewed by members in the General Assembly. The 10th interview, of Figueres, is scheduled for Thursday.