The Iranian president said that al-Faisal was not following the orders of Saudi King Abdullah with his remarks.
"Iran is the only country not interfering in Lebanon," he told a news conference.
Earlier on Tuesday, Saudi Arabia had blamed Iran for Hezbollah's routing of the Western-backed government supporters in Lebanon.
Lebanon has suffered from almost a week of clashes between supporters of the Western-backed government and the opposition Hezbollah movement, backed by Iran and Syria.
At least 54 people have died in the battles and scores more have been injured.
Hezbollah has overpowered supporters of the government in Beirut and hills to the east.
Nuclear 'proposals'
Ahmadinejad also said that Iran will soon put forward new proposals to resolve its dispute with the West over its nuclear programme.
"We have prepared a package which will soon be offered."
However, he said that no incentives offered by the West would persuade Iran to abandon its right to develop its nuclear programme.
Iran says that the programme is to create nuclear power, whereas the West fears that its real aim is to develop nuclear weapons.