The International Committee of the Red Cross says the situation for ordinary Iraqis is getting steadily worse.
The current security situation is disastrous, the Red Cross says
Four years after the US-led invasion, the ICRC says the conflict is inflicting immense suffering, and calls for greater protection of civilians.
An Iraqi woman quoted in the report said people wanted help to collect bodies lining streets every morning.
The ICRC still has a presence in Iraq despite the bombing of its Baghdad offices three and a half years ago.
In the report called Civilians Without protection - The Ever-worsening Crisis in Iraq, the Red Cross asked Iraqis what could be done to help them.
The answer was a shock, says ICRC director of operations Pierre Kraehenbuehl.
"The suffering that Iraqi men, women and children are enduring today is unbearable and unacceptable," he said.
"The ICRC calls on all those who can influence the situation on the ground to act now to ensure that the lives of ordinary people are spared and protected. This is an obligation under international humanitarian law for both states and non-state actors."
The famously neutral International Red Cross will not blame anyone in particular for what it calls the current disastrous security situation, says the BBC's Imogen Foulkes in Geneva.
The report makes it clear that nobody - including the Iraqi government and coalition forces - has done enough so far, our correspondent adds.
Red Cross workers asked Iraqi women about their lives.
"If there's anything that anybody could do that would really help us today would be to help us collect the bodies that line the streets in front of our homes every morning and that we find nobody dares to touch or remove after security reasons," one woman said.
Women found it "simply unbearable" to confront their children with them morning after morning as they tried to take them to school, the woman added.
The Red Cross says every aspect of life in Iraq is getting worse - a trip to the market has become a matter of life and death.
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"Once I was called to an explosion site," Saad, a humanitarian worker, is quoted as saying in the report.
"There I saw a four-year-old boy sitting beside his mother's body, which had been decapitated by the explosion. He was talking to her, asking her what had happened. He had been taken out shopping by his mum."
The report also highlights the following problems:
- Iraq's healthcare facilities face critical shortages of staff and supplies. Many doctors, nurses and patients no longer dare to go to hospitals and clinics because they are targeted or threatened
- much of Iraq's vital water, sewage and electricity infrastructure is in a critical condition
- food shortages have been reported in some areas and malnutrition is said to have increased
In a report also released on Wednesday, the charity Oxfam said the UK's ability to be a force for good in the world had been seriously damaged by the invasion of Iraq and other foreign policy decisions.
And a report by the Oxford Research Group think tank said UK and US policy towards Iraq had "spawned new terror in the region".