Samahnews.org said the sentence was upheld against Davari who was arrested in September 2009 for “propaganda against the regime and gatherings aimed at damaging national security and public order.”
The website did not say when the verdict was delivered.
He was arrested after Karroubi charged that several detained male and female demonstrators had been raped, tortured and killed in Kahrizak detention centre during post-election unrest last year, it said.
Davari is being held in Tehran’s Evin prison.
The scandal at Kahrizak, south of the capital, caused major embarrassment for Iranian officials, who after months of denial acknowledged that at least three protesters had died there from custodial injuries.
The centre was shut down in July 2009 on the orders of the Islamic republic’s supreme leader, Ayatollah Ali Khamenei.
Iranian authorities have cracked down on the media and journalists since the June 2009 re-election of President Mahmoud Ahmadinejad, which the opposition dismissed as massively rigged, sparking street protests.
