Upon his return, Dembri took over the post of Minister of Foreign Affairs from Redha Malek in 1993, who in turn took up the post of Prime Minister on 23 August 1993 and formed a new government. Until 1996, Dembri also held the post of Minister of Foreign Affairs in the following governments of Prime Ministers Mokdad Sifi and Ahmed Ouyahia.
He then became Permanent Representative to the United Nations Office at Geneva in 1996 and remained in this post until 2005. At the same time, Dembri was accredited to the Holy See between 1997 and 2004. He was in 1999 President of the Conference on Disarmament UNCD (United Nations Conference on Disarmament) and between 2000 and 2001 president of the local working group for development rights, then from 2001 to 2003 President of a group of work of the Commission on Human Rights, before 2004 President of the Executive Committee of the 101st session of the International Organization for Migration (IOM).