U.S. President George W. Bush proposed the peace conference in July, but Washington has given few details of what it expects from it.
U.S. officials are trying to lower expectations and have shifted attention to preparatory bilateral meetings between Israeli and Palestinian leaders.
“The death knell of such ineffective conferences is being heard,” Ayatollah Ahmad Khatami told worshippers at Friday prayers in Tehran.
Iran does not recognize Israel and opposes the U.S.-backed Middle East peace process, accusing its arch-foe Washington of bias towards the Jewish state at the expense of Palestinians.
“These conferences are not looking forward towards solving the Palestinian people’s problems, they only anticipate solving Israel’s problems,” said the hardline cleric.
The Islamic Republic had toned down its opposition to the peace process under moderate President Mohammad Khatami, who said it was up to the Palestinians to decide on their future.
But President Mahmoud Ahmadinejad, who came to power in 2005, has rarely missed an opportunity to lambast Israel, predicting its destruction although he has also said Iran is not a threat to the Jewish state.
Some Arab states have questioned what the planned conference, expected in November, can achieve.
Saudi Arabia has hinted it might not attend and Arab League chief Amr Moussa, who represents the consensus of 22 Arab governments, said Arabs want more than gimmicks.
“I tell some of the Palestinian groups … having ties with Israel brings nothing to you except degradation,” said the ayatollah, holder of one of the highest Shi’ite Muslim clerical ranks.
Iran has been a financial backer of Hamas while it was in government, even as other mainly Western donors abandoned the Palestinian government when the Islamist group was in control.
Iran’s Foreign Minister Manouchehr Mottaki blamed the United States and other foreign parties in June for the crisis between Hamas and the secular Palestinian group Fatah.
