The semiofficial Mehr news agency says Bashir will arrive in the Iranian capital on June 25 to participate in the forum -- which is titled Global Campaign against Terrorism Conference -- as a "special guest" because his country has faced terrorist attacks.
Bashir became the first sitting head of state to be targeted by the ICC in March 2009 when the court issued an arrest warrant for him on counts of war crimes and crimes against humanity in Darfur.
Not everyone seems to be happy with the decision to invite the Sudanese leader to Iran, though.
The website Asriran, which is said to be close to Tehran Mayor Mohammad Bagher Qalibaf, has said in a commentary that Bashir should not be allowed to travel to Iran because of his war-crime dossier.
Asriran compares Bashir with war criminals from the former Yugoslavia and Libyan leader Muammar Qaddafi, and he says that Bashir's trip to Iran will come at a cost.
"In the current situation, in which Iran is being strongly accused of human rights abuses by Western countries and news-making against Iran in that area continues, the trip to Tehran by one of the most prominent human rights abusers in the world will have many costs for Iran," the website argues. "The dignity of the Iranian people is much more valuable than hosting in its capital someone who is accused of killing thousands of people and its authorities having photo ops with him."
Asriran says Iran should cancel Bashir's visit.