The brief bout of pushing and shouting on Sunday involved around a dozen deputies. But it reflected simmering political tension following parliamentary elections last month which reformists allege were rigged in advance to ensure a conservative victory.
Conservative candidates secured a comfortable majority at the polls, reversing a reformist win in 2000 elections, after more than 2,000 mainly reformist aspirants were barred from standing for election by a watchdog run by religious conservatives.
Outspoken reformist deputy Ali Akbar Mousavi-Khoeini, one of several dozen reformist legislators barred from standing for re-election, called on Iran's Assembly of Experts to decide whether Khamenei had acted properly over the election dispute.
Reformist allies of President Muhammad Khatami have questioned whether Khamenei, who has the last word on all state matters, tacitly supported the conservative Guardian Council's decision to ban hundreds of reformists from the election race.
"The assembly should examine if the leader and the council's moves were based on justice and expedience," he told a parliament session, broadcast live by state radio.
The Assembly of Experts, a body of around 86 senior clerics which began an annual meeting in Tehran on Sunday, appoints Iran's supreme leader and is empowered to dismiss him if he is deemed to be performing badly or is unfit to hold the office.
Tehran has been simmering with
political tension for months
But criticism of the supreme leader is considered anathema by conservatives.
As Mousavi-Khoeini addressed parliament several conservative deputies stormed the lectern and pulled away his microphone. A mêlée ensued during which deputies traded shoves, kicks and insults. There were no injuries, witnesses said.
Doomed to lose their tribune in parliament when the newly-elected assembly convenes in June, reformist lawmakers have spoken out more openly in recent weeks.
Criticism of the Guardian Council, an unelected 12 member body of conservative clerics and jurists, has landed at least three reformist deputies in legal trouble, newspapers said on Sunday.
The three outgoing legislators, Muhammad Reza Ali-Hosseini, Ali Mohammad Namazi and Elyas Hazrati, have been summoned to court to face charges such as spreading lies and speeches and articles criticising the council and the conduct of the polls.
In a sign that the Assembly of Experts was very unlikely to take Khamenei to task, the secretary of the assembly Ayat Allah Ali Meshkini hailed the parliamentary vote as a "glorious" event.
"The revolution and Islam would have been harmed if it were not for the leader's wise guidance, the people's devotion ... and the Guardian Council's resolve," he told the assembly meeting, according to the ISNA student news agency.