The Rome-based Hands Off Cain group, which campaigns to stop the death penalty, said last week that at least 355 people were put to death in Iran last year, compared with 215 in 2006.
The group said the actual figure may be even higher because Iran does not publish official statistics on the number of executions.
The 355 executions placed Iran second only to China as the world's biggest executioner.
The state broadcaster said the latest death sentences were approved by the Tehran revolutionary court and high judicial authorities.
"We have demonstrated our serious determination to combat organised, international and group crimes which disturb order and the security of our citizens," Saeed Mortazavi, Theran's chief prosecutor, told the state broadcaster.
On Saturday, the media reported that 30 people would be executed, saying 20 were drug traffickers and the rest were "murderer thugs".
Earlier this month parliament was reported to be considering a bill which could see the death penalty also being imposed on those deemed to promote corruption, prostitution and apostasy on the internet.