Displaced Iraqis who escaped a jihadist-led onslaught north of Baghdad during the scorching summer are braced to face another enemy: the onset of winter in the mountains of Iraqi Kurdistan.

At the newest camp in Khanke, a few kilometres (miles) from the Turkish border in Iraq's Dohuk province, lorries have been ferrying in equipment to house the displaced people with some degree of winter-proofing.

Run by authorities from the three-province autonomous Kurdish region of north Iraq with the help of the United Nations refugee agency, the UNHCR, Khanke aims to house 18,000 people, said the agency's Liena Veide.

"Winter is coming... We have to be prepared because it seems these people are staying," she said, as the first tents with solid floors and walls were being erected to deal with the cold to come after the seasonal rains of late October.

When people made their long and often gruelling journey to safety this summer, the mercury sometimes hovered at a debilitating 50 degrees Celsius (122 Fahrenheit).

But temperatures plunge from early autumn in the valleys and mountains of Kurdistan, where snow can fall as early as November.

Iraqi troops, Shiite militias and Kurdish forces, backed by US air strikes, are battling to regain ground lost to a sweeping offensive led by the Islamic State (IS) jihadist group that overran major parts of the country.

While these forces have made some progress, there is no end to the conflict in sight, and displaced people are not expected to be able to return home before the onset of winter.

The UNHCR estimates that Dohuk province has taken in more than 550,000 people who have fled the violence, and displaced families living in some 600 schools will now be given priority for the winter-proofed tents.

Since the militants launched their offensive in provinces north and west of the capital in June, people have also taken shelter in construction sites, mosques or simply on the roadside.

- 'Where can we go?' -

"I don't know what to do," said a distraught Bapir Rashwe Ravo, who fled from Sinjar when IS targeted members of the Yazidi religious minority in the area.

Two Iraqi 1,000-dinar notes (less than $2) make up the combined fortune of Ravo and his extended family of more than 30 members who are being housed in Khanke, and food is lacking.

"We can't stay here much longer but where can we go?" said the bearded 44-year-old.

The deprivations of camp life weigh heavily on children, many of whom witnessed at first hand the horrors of conflict.

"These children need schools, care, food... All they have here is tents," said Lokman Atrashi, who works at the Swedish Specialist Hospital in the Kurdish regional capital of Arbil, as he entered the camp with toys for the children.

"They have nowhere to go, everything's been destroyed. Just ask the children what they've seen -- it's tragic," he said.

When the jihadists attacked Yazidi villages near the Syrian border in early August, people flooded into the safety of the Kurdish region, many bringing nothing but the clothes they wore.

Other people did not make it out at all, with many killed or kidnapped and some women reportedly sold into slavery.

The UNHCR said last week it is organising a massive aid operation in Iraqi Kurdistan to help the estimated 850,000 people who have sought refuge in the region.

The agency's spokesman, Adrian Edwards, told reporters in Geneva that there was an "acute" need for accommodation and it was a race against the clock.

In the UNHCR's largest single aid push in more than a decade, blankets, kitchen sets and plastic sheets have flowed in by plane, ship and road.

"Where are all the big aid organisations?" asked Atrashi. "There are some UN agencies but this is just not enough."