Iran has been swept by protests since the death of a young Iranian Kurdish woman, Mahsa Amini, in custody last September.
Addressing the Geneva-based council, Javaid Rehman, Special Rapporteur on Iran, said he had evidence that Amini died "as a result of beatings by the state morality police".
Rehman, an independent expert, added that the scale and gravity of crimes committed by authorities as part of the repression following her death "points to the possible commission of international crimes, notably the crimes against humanity".
People hold flags during a demonstration against the Republic of Iran in the Place des Nations during the Human Rights Council at the United Nations in Geneva, Switzerland, February 27, 2023.
Evidence assembled by other investigations set up by the U.N. rights council has sometimes been used before international courts.