Syrian refugee children are suffering both physically and psychologically and many are the sole breadwinners in their family, working for little pay in dangerous and exploitative conditions, a new UN report says.

The 62-page document, titled The Future of Syria - Refugee Children in Crisis and published by the UN High Commissioner for Refugees, says UN agencies have reached out to over 250,000 refugee children across Jordan and Lebanon with various forms of psychosocial support.

More than 1.1 million Syrian children are registered as refugees with UNHCR worldwide, the report stated.  Of this number, some 75 per cent are under the age of 12. Children represent 52 per cent of the total Syrian refugee population, with many living in crammed apartments, makeshift shelters or tents. Almost 30 per cent of children interviewed for the report said they only leave their home once a week or less.

"The conflict in Syria has caused Syrian girls and boys of all ages to suffer immensely, both physically and psychologically," the report says. 

"They have experienced first-hand conflict, destruction and violence. The psychological effects of such horrific experiences can be far-reaching, affecting their well-being, sleep, speech and social skills."

In the first six months of 2013, 741 Syrian refugee children received hospital treatment for physical trauma and other injuries incurred in Syria or Lebanon, including burns, bullet wounds and broken bones, according to the report.

Meanwhile, hundreds of children are living without one or both parents or with no adult caregivers at all.

By the end of September 2013, UNHCR had registered more than 3,700 unaccompanied or separated children in Lebanon and Jordan.

As well, many children, out of financial necessity for their families, are forced to work,  Around one in 10 Syrian refugee children are child labourers, according to UNICEF estimates. Many children, including those that are as young as seven, are working long hours, in "hazardous or demeaning environments" while some are mistreated in the workplace, the report says.

Access to education is also an issue, with 80 per cent of Syrian refugee children in Lebanon not in school and more than 100,000 Syrian school-aged children in Jordan not enrolled, the report found.

“If we do not act quickly, a generation of innocents will become lasting casualties of an appalling war,” said UN High Commissioner for Refugees António Guterres in a statement.