Over 900,000 people have been affected by floods in 29 counties across South Sudan and in the southern part of the Abyei administrative area, the UN Office for the Coordination of Humanitarian Affairs (Ocha) says.
It says the worst affected states are Northern Bahr El-Ghazal, Warrap, Unity and Western Equatoria.
Increasing water levels reported in Rubkona and Bentiu towns in Unity State were putting pressure on existing dykes, the UN agency said.
It added that the collapse of a key bridge in Western Bahr El-Ghazal State continues to hamper humanitarian response to some 50,000 people living in the area.
Funding shortfalls and insecurity have hampered humanitarian work, Ocha added.