The refugees, sheltering in the town of Aru in Ituri province in the Congo, fled fighting along the border between South Sudan and Uganda.
Fighting has persisted between the government forces and rebels of the National Salvation Front which rejects the peace accord between the South Sudan President Salva Kiir and his arch-foe Riek Machar.
Authorities say 554 people have arrived since the start of the month and they are among nearly 100,000 South Sudanese refugees in the Congo's Haut Uele and Ituri provinces, according to the UNHCR.