The Guardian Council spokesman also told state radio the 12-member body had begun to carefully examine a total of 646 complaints submitted in connection with the June 12 vote, which official results showed President Mahmoud Ahmadinejad won.
Ahmadinejad's main challenger in the election, moderate Mirhossein Mousavi, has called for the vote to be annulled.
The council has said it is ready to recount disputed ballot boxes but has ruled out cancelling the election.
The two other defeated candidates are pro-reform cleric Mehdi Karoubi and conservative Mohsen Rezaie, a former head of Iran's Revolutionary Guards.
Guardian Council spokesman Abbasali Kadkhodai said the three candidates would be able to raise their problems with the council's members at an extraordinary meeting on Saturday.
Complaints submitted include a shortage of ballot papers, trying to convince or force people to vote for one particular contestant and banning or expelling candidates' representatives from polling stations, Kadkhodai said.
"We have begun the careful examination of the communicated complaints and the classification of complaints has begun," he told the radio.
The council consists of six senior clerics appointed by Supreme Leader Ayatollah Ali Khamenei and six Islamic jurists.
It must ensure all laws passed by parliament agree with Islamic Sharia law and Iran's constitution. It also vets aspiring candidates for presidential elections, and must approve the election results.
(Reporting by Hossein Jaseb and Hashem Kalantari; writing by Fredrik Dahl; editing by Philippa Fletcher)
