The civilians originally hailed from Hawija but had fled fighting against the Islamic State group years ago to Hammam al-Alil camp, about 150 kilometres (100 miles) north.

Early Wednesday, Iraqi officials and security forces began guiding camp residents to more than a dozen white buses bearing the emblem of Iraq's ministy of transport.

Women in black robes and young children carried their meagre belongings and queued outside the buses, some of them crying, as officials checked their names against a list of those expected to leave.

"We are being returned to our areas. Maybe I'll have to live in a camp there because my house is destroyed," said Umm Hikm, a 65-year-old displaced woman who had been living in the camp for two years.

More than 150 families, or around 550 individuals, would be taken back to Kirkuk province as part of the transfer, said Ali Khodr, the associate governor for displacement.

"A few days ago, 35 families were returned to (the western province of) Anbar. We are working on returning the rest of the displaced to their provinces of origin," he told AFP.

More than 1.6 million people remain displaced in camps, unfinished structures or rented apartments across Iraq nearly two years after the country declared IS defeated.

The government has stressed its policy is for all displaced to return home, but many of their areas of origin remain heavily destroyed, with few services.

After several hours in Iraq's baking sun, the buses left for Hawija, according to the Norwegian Refugee Council (NRC) which manages Hammam al-Alil and was monitoring the transfers.

NRC's Iraq media coordinator Tom Peyre-Costa said the group was very concerned about the process, as the displaced often had no homes to return to and feared retaliation from their communities for perceived ties to IS.

"They are scared, and most families from Hawija leaving today are undocumented," he said, speaking to AFP in Baghdad from the camp.

"Going home without documents means they will not have access to anything -- children won't be able to go to school, no access to health care, no food distribution."