"In the time left (until Friday's poll), it seems necessary that the nation's and your demand to hold clean and glorious elections with high turnout be met," Rafsanjani said in a letter to Iran's supreme leader, Ayatollah Ali Khamenei.
"This can save the country from dangers and create national trust and unity."
The letter followed a rejection of Rafsanjani's request to reply to verbal attacks by President Mahmoud Ahmadinejad during a live televised debate against him.
During last Wednesday's debate with moderate challenger Mir Hossein Mousavi, Ahmadinejad charged that some of Mousavi's supporters, especially sons of Rafsanjani, had received financial privileges in the past.
The incumbent, who is seeking a second four-year term, also said he and his government had come under sustained attack from Mousavi and his supporters, who include Rafsanjani and reformist former president Mohammad Khatami.
On Sunday, Rafsanjani's office complained over the refusal state television head Ezatollah Zarghami, who did not give the influential cleric an immediate platform to respond to the allegations.
Khamenei has implicitly voiced support for Ahmadinejad, urging the nation to vote for anti-West candidates who live in a simple and modest way — traits attributed to the president.
