GENEVA - Food, water and shelter are obvious basic needs for people fleeing war. But with refugees now spending roughly 20 years in exile on average, the UN refugee agency is calling on the world to do more to ensure refugee children have access to education as a fundamental right.

Over 3.7 million school-age children, or about 62 per cent of the children covered under the mandate of the United Nations High Commissioner for Refugees, have no schools to attend, the agency said in a report issued Thursday.

Entitled "Missing Out: Refugee Education in Crisis," the 48-page report's release comes as the UN General Assembly is preparing to host a summit on refugees and migrants in New York next week.

UN High Commissioner for Refugees Filippo Grandi says that while education is vital for all children, it's especially crucial to help equip refugee children to succeed in work and life.

"Education is also a key contribution to keeping the hope of refugees, and in situations in which despair is so prevalent, going to school, learning, acquiring knowledge and skills, are fundamental," Grandi told The Associated Press in an interview Tuesday.

Comparing its own count of children attending school with global figures by the UN educational agency, UNHCR estimated that only half of all refugee children have access to primary education - compared to a world average of over 90 per cent. And that rate only gets worse as refugee children get older.

Fewer than one in four of refugee adolescents attend secondary school compared to a global average of 84 per cent, and only 1 per cent of refugees attend university compared to about one in three people worldwide, according to the comparison with UNESCO figures.

"The average length of time a refugee spends in exile is about 20 years," Grandi wrote in the report's introduction. "Given this sobering picture, it is critical that we think beyond a refugee's basic survival."

The report calls on charitable donors to take a longer-term approach by providing multi-year and not just emergency funding.

The UN refugee agency said about 86 per cent of the world's refugees are hosted in developing regions, while over half of the out-of-school refugee children are located in just seven countries: Chad, Congo, Ethiopia, Kenya, Lebanon, Pakistan and Turkey.

Pointing to a growing population of school-age children worldwide over the last five years, the report says that countries seeing in an influx of refugees face a struggle of "sheer numbers."

While noting that host countries for refugees already face difficulties educating their own children, the report urges governments to make plans for including refugee children in their education systems.