One million displaced within the country and 378,000 seeking refuge in Ethiopia, Kenya, Sudan and Uganda.
But agency warns that deal must lead to improved humanitarian access, as five million people are "in urgent need of aid".
Ban Ki-moon and Pope Francis to discuss fight against poverty and inequality.
People have been catapulted into dire suffering, unable to return to their homes, and now in urgent need of food, clean water and shelter.
Pontiff asks for prayers for an end to injustice towards the hungry and the vulnerable.
"Living in Ethiopia is like living in America compared to South Sudan.”
"People are on the edge of starvation. This conflict has been devastating and very inhuman" - Mgr Roko Taban Mousa.
Irish charity, Misean Cara, funding teaching project
Cardinal Brady discusses fraternity and the impasse in NI talks in New Year's homily.
Concern 'monitoring situation' as clashes continue in capitals of oil producing states.
Pontiff called on God to protect the earth “frequently exploited by human greed and rapacity.”
UN base in Jonglei state besieged as five days of violence leaves over 500 dead.