“There are possibly more than 500 cases being prepared against Saddam Hussein, but there is no reason to waste time in dealing with them all,” government spokesman Leith Kubba told reporters.
“We are completely confident that the 12 fully documented charges that have been brought against him are more than sufficient to ensure he receives the maximum sentence.”
The former dictator faces a litany of accusations including a 1988 chemical attack on the Kurdish village of Halabja, the repression of a 1991 Shiite rebellion and the 1990 invasion of Kuwait.
He could face the death penalty if found guilty. His trial should begin within two months, the spokesman said.
Mr Kubba also said Operation Lightning had helped stabilise Baghdad and had been expanded.
More than 1,200 suspects had been detained since the start of the operation.
Almost 700 Iraqis were killed throughout the country in May, one of the deadliest months since the US-led invasion of March 2003.
Meanwhile, 50 weapons caches were found in the bunker complex in an abandoned quarry in Karmah, west of Baghdad.
Fully furnished living spaces were found, along with a kitchen, showers and hi-tech combat equipment such as night vision goggles, black uniforms, ski masks, cell phones and a large haul of weapons and ammunition.
The complex, 170 metres wide and 275 metres long – larger than four football pitches – was found unoccupied but fresh food indicated it had been recently inhabited.
In a separate operation, the Iraqi government announced the arrest of two senior members of the group of Abu Musab al-Zarqawi, the alleged leader of al-Qaeda in Iraq.
Motleq Mahmoud Motleq Abdullah, also known as Abu Raed, was arrested in Mosul on May 28, and Mullah Mehdi, who is not an Iraqi, was captured on Friday in eastern Mosul.