Crowding in Iraqi camps for Syrians who have fled their war-ravaged homeland is raising the risk of disease.

Crowding in Iraqi camps for Syrians who have fled their war-ravaged homeland is raising the risk of disease, the UN refugee agency warned Tuesday.

"Pressure to accommodate refugees is growing," said Adrian Edwards, spokesman for the office of the UN High Commissioner for Refugees.

"The crowding is in turn having an impact on sanitation, which is already below humanitarian standards. Congestion and warmer temperatures are increasing vulnerability to outbreaks of diseases as well as to tension between camp residents," he told reporters in Geneva.

As of the end of March, a total of 121,320 Syrian refugees were registered in Iraq, Edwards said, with 90 percent of them hosted in the country's Kurdistan region.

The situation at a camp at Domiz, in northwestern Iraq, is particularly worrying, he noted.

"The Domiz camp is currently housing around 35,000 Syrian refugees and is critically overcrowded. Thousands of families are sharing tents with newly arrived refugees as almost 3,500 families do not have their own shelters," he said.

Authorities in Iraq's Erbil and Sulaimaniyah provinces have announced that they will provide more space for refugees there.

"However, the allocated space can accommodate only 25,000 people -- or only one third of the need," Edwards said.

He stressed that while concerns focus on the situation in refugee camps, more than 60 percent of the Syrians registered in the Kurdistan region are being hosted by Iraqi communities or are living in unfinished houses or apartments.

"The hospitality and support to Syrian refugees demonstrated by the government and the people of Iraq has been extraordinary," he said.