The three young people, selected by the Foreign Office to attend the New York event, will represent the UK when the UN reviews the progress made in implementing its World Programme of Action for Youth - 10 years after its adoption.
The programme outlines the role that member states need to play in supporting disadvantaged young people, tackling youth unemployment and increasing young people's participation in decision making.
The youth delegates were recruited via a web site set up by the UN Youth and Students Association UK and through interviews with Foreign Office staff. The delegates will meet Foreign Office officials this week to discuss how they can gather the views of their peers to take to the assembly, as well as provide feedback to them on their return.
"This is more than just a gesture; they're going to be working very hard," said a Foreign Office spokesman. "We're developing a full role for them to play, not just when they get to New York, but in the run-up to the event."
One of the delegates, 19-year-old Frederick Bernas from west London, said one of the first tasks would be creating a youth-friendly version of the programme. "There's a lot of important stuff in there about education, facilities for young people and youth participation," he said.
www.un.org/youth.