Ahmed Shaheed, the Geneva-based UN Human Rights Council’s special reporter on Iran, also called for an “extensive, impartial and independent investigation into the violence in the weeks and months that followed the presidential election of 2009″.
Pro-democracy protesters had surged onto the streets to denounce the election of president Mahmoud Ahmadinejad.
Mr Shaheed also reiterated his call for the immediate release of all political prisoners and prisoners of conscience, according the report.
The document will be the basis for a General Assembly resolution criticising Tehran’s human rights record.
Mr Shaheed reported that at least 150 journalists have fled Iran since the 2009 elections, and some reports put the number as high as 400.
Iran detained more journalists than any other nation last year.
Iran is also cracking down on internet users, with Mr Shaheed reporting that 19 bloggers and internet commentators are currently under arrest in the Islamic Republic.
Four of those –Vahid Asghari, Ahmad Reza Hashempour, Mehdi Alizadeh Fakhrabad and Saeed Malekpour – were sentenced to death in January.