The World Bank has given South Sudan $50 million to address food insecurity and malnutrition.
The UN Food and Agriculture Organisation (FAO), Unicef and WFP said in a statement, the World Bank's support, channelled through South Sudan's Ministry of Agriculture, was vital to maintain the momentum of helping millions who would face starvation.
However, six million people still did not know where their next meal would come from.
Across the country, more than 1.1 million children were estimated to suffer from malnutrition, with almost 290,000 severely malnourished and in need of urgent humanitarian aid.
"With half of South Sudan's population struggling to feed itself and more than one million children suffering from acute malnutrition, this is vital assistance that will save many lives, while helping communities to help themselves," said Mr Mahimbo Mdoe, the Unicef Representative in South Sudan.
WFP will receive nearly $26 million for food and nutrition assistance to 110,000 people, particularly in areas with acute hunger and threatened by famine.
"Thanks to the funding from the World Bank, we can work towards a sustainable future by supporting the most vulnerable farmers, pastoralists and fisher folk rebuild their livelihoods," said Mr Serge Tissot, the FAO Representative in South Sudan.
FAO will receive nearly $8 million to support the recovery of crop, livestock and fisheries production in areas hard hit by food insecurity. By restoring their livelihoods, ending hunger and extreme poverty can become a reality.
The World Bank, through this contribution, is supporting the government's South Sudan Emergency Food and Nutrition Security Project to ensure an integrated response to crisis levels of food insecurity and malnutrition across South Sudan, and especially in Upper Nile, Jonglei and Unity states.
The UN agencies said they would have individual agreements with the government, but would work closely together in the emergency response.
WFP has assisted 4.2 million people in South Sudan so far this year - the highest number reached by by the agency since independence in 2011. In July, WFP provided food and nutrition assistance for 2.9 million people.
FAO has assisted 3.9 million people with emergency livelihood kits (fishing, vegetable and crop), and reached 3.1 million livestock under an animal health campaign.
In the coming months, FAO will be scaling up its response to farmers in the second planting season in the Equatorias.
Unicef has ensured 1.5 million children (aged 6 to 59 months) received vitamin A supplementation, and more than 1.1 million children (aged 12 to 59 months) received Albandazole-deworming tablets, in 2017.
Unicef has also assisted more than 120,000 children since January this year, who were admitted into outpatient therapeutic programmes and stabilisation centre services across the country for the treatment of severe acute malnutrition.