Rafsanjani, one of the main figures in Iran's opposition movement, also called on protesters opposing the re-election of President Mahmoud Ahmadinejad to express their views "within the framework of law."
"The situation in the country is such that constructive criticism is not accepted," Rafsanjani told a gathering of students in the northern city of Mashhad, according to ILNA news agency.
He urged the Islamic republic's various political factions to unite and work within the law in order to "create a climate of freedom which will convince the majority of people and erase ambiguities."
"Those who demonstrate or protest must express themselves through legal means. Leaders must also respect the law," Rafsanjani said on the eve of the annual Students Day when fresh demonstrations are expected against Ahmadinejad.
"There have always been extremist factions and excessive attitudes on both sides… but several problems will be solved if we adopt the path of moderation," said the cleric.
Iran was thrown into one of its worst crises since the Islamic revolution when hundreds of thousands of people poured onto streets of Tehran to oppose Ahmadinejad's re-election in June.
Thousands were arrested by authorities and dozens were killed in clashes which erupted after the June 12 poll which Ahmadinejad's opponents say was rigged to ensure his victory.
