Tehran says it has drawn its own list of charges against Saddam Hussein for crimes relating to the Iran-Iraq war.
It is not clear when Iran will submit the complaint to the court
The charges - to be submitted to the Iraqi court which is trying the ousted leader - include the 1980 attack on Iran and the use of chemical weapons.
Almost a million people died in the eight-year war between the two nations.
A spokesman said Iran had asked why alleged crimes against Iran were not among charges read out during Saddam Hussein's court appearance on Thursday.
"Iran will definitely file the complaint with the Iraqi court," a Foreign Ministry spokesperson said.
"One of the crimes of Saddam Hussein is the attack of Iran, the death of Iranians, the use of chemical weapons," Hamid Reza Asefi told reporters.
Mr Asefi said Tehran wanted to know why charges relating to the Iran-Iraq war had not been included in the original list read out to Saddam Hussein.
"We have asked the Iraqis to explain why the attack on Iran did not feature among the charges against him, even though the judge said it would be addressed at a later date," Mr Asefi said.
Anfal campaign against Kurds, late 1980s
Gassing Kurds in Halabja, 1988
Invasion of Kuwait , 1990
Crushing Kurdish and Shia rebellions after 1991 Gulf War
Killing political activists over 30 years
Massacring members of Kurdish Barzani tribe in 1980s
Killing religious leaders, 1974
Saddam Hussein appeared on Thursday in a court specially set up to try him and was told by an Iraqi judge that he would face charges relating to seven alleged crimes.
Iran said it would also hand over documents to the Iraqi court where Saddam Hussein is standing trial, although it was not made clear exactly when the complaint would be lodged.
Preliminary charges against Saddam Hussein cover the invasion of Kuwait in 1990, suppressing rebellions by Kurds and Shia after the 1991 Gulf war, ethnic cleansing of Kurds in 1987-88 and the gassing of Kurdish villagers in 1988.