Jamal Benomar has reportedly "expressed an interest in moving on to another assignment," thus taking leave from the chaotic security and political situation in the country.
Benomar, who is a Moroccan diplomat and spent eight years in jail as a political prisoner, had been acting as a mediator among factions in Yemen.
The UN representative had come under criticism from certain Arab states, Saudi Arabia in particular, for his little success in influencing the political scene in Yemen in their favor.
Saudi Arabia launched its military aggression against Yemen on March 26, without a UN mandate, in order to restore fugitive former president Abd Rabbuh Mansur Hadi to power.
The main candidate for the post of special envoy to Yemen is said to be Ismail Ould Cheikh Ahmad, a Mauritanian diplomat, Press TV reported.
Ahmed has served as the United Nations deputy-special envoy for Libya since January 2014. In December of the same year, he was appointed as the chief of the UN Mission for Ebola Emergency Response (UNMEER).
Meanwhile, the humanitarian situation in Yemen has become dire with thousands of people killed and many more wounded, and not receiving adequate medical treatment. This has resulted in public outcry with many international aid organizations seeking a safe passage into the country to send much-needed medical and humanitarian supplies to the suffering nation.