Security sources on Tuesday said the remains of 22 people had been uncovered near Najaf, where a number of mass graves have been found since the fall of Saddam Hussein in April 2003.
They are believed to be victims of a violent repression by Saddam's government of a Shia uprising in 1991 following the first Gulf war which rid Iraqi invasion troops from neighbouring Kuwait.
One source said: "The remains were found by accident at a building site in the Kifl region on the road between Najaf and Karbala.
"A search is ongoing to find other bodies," the source said, adding that at least five mass graves dating back to 1991 have been found in the region in recent years.
Meanwhile, violence across the country left at least 12 Iraqis dead.
Seven Iraqis preparing rations for the Iraqi army were killed by armed men in an assault on their small factory in Baghdad.
In Kirkuk, armed men hit the offices of the anti-corruption department killing a security guard and wounding another, while the office of the Kurdish Solution party was also attacked, killing one and injuring two others.
An al-Qaida linked group, Ansar al-Sunna, claimed it had killed three members of the Patriotic Union of Kurdistan in Kirkuk but there was no independent confirmation.
A US army convoy just north of Karbala was also targeted by a roadside bomb wounding four soldiers and one civilian contractor, the US military said.
In Baghdad, another bomb wounded five civilians while a series of shootings resulted in the deaths of three policemen.