Speaking to the charity Tearfund, Bishop of Twic East, Rt Rev Ezekiel Diing Ajang Malangdit, said there was an urgent need to help feed those facing starvation.
He said: "Hunger is the number one issue. People are very hungry but they do not want to leave their homes. There are also other problems such as water and sanitation. Children are dehydrated, women are dying, there is no medication for pregnant women and new mothers who are still breastfeeding."
South Sudan has been embroiled in civil war for over three years. The conflict is driving the devastating famine that is threatening millions with starvation, according to the UN.
The war has displaced more than 3.5 million South Sudanese people. It is estimated that at least 4.9 million are going hungry in the country.
"There is not enough food now," Rev Ezekiel said, "People are hungry. So we need urgent support now, especially for people who have been internally displaced. There is an urgent need for relief.
"It is important to strengthen people and give them the knowledge to do things by themselves so that they can support themselves instead of relying on other people.
"Empowerment of the community and empowerment of the Church is important."
Famine has been declared in parts of South Sudan and Yemen, Somalia and parts of North East Nigeria have been ranked as "at risk" for famine if significant humanitarian assistance is not urgently offered.
With 20 million people facing starvation across the region, UN officials have warned that the world faces the worst humanitarian crisis since the end of the Second World War.
On Sunday, the UN reported that six aid workers were ambushed and killed in South Sudan.
At least 12 aid workers have been killed so far this year and 79 have been killed since the civil war began.