The head of the United Nations mission in South Sudan says food shortages and famine being faced in some parts of the country is all about man made problems which have led to conflict and displacement.

Speaking to reporters in Juba, David Shearer confirmed the serious nature of food shortages in Unity State and areas around Leer.

He said the number of people in need of food aid around the country has risen by half a million from last year to 5.5 million.