In the six years since the country gained independence, its government has imploded, famine has been declared, and thousands of refugees are streaming into neighbouring countries.
Angelina Teny, the wife of former vice-president Riek Machar, is in Australia lobbying the Government and the South Sudanese community here to step up aid.
"Genocide is in progress. I'm not sure what the world is waiting for," she told Lateline.
"The Minister of International Development of the UK visited about five weeks back and clearly stated that genocide is fully fledged."
Ms Teny and her husband fled the capital Juba last year, after Machar was sacked by president Salva Kiir. Machar is now under house arrest in South Africa.
Machar is from the ethnic Nuer group, while Mr Kiir is an ethnic Dinka. Allegations of war crimes have been made against troops loyal to both Machar and Mr Kiir.
'They're dying of starvation'
Ms Teny said it was seriously concerning that the Federal Government cut foreign aid in last week's budget and she called on Australia not to withdraw humanitarian assistance.
"They're dying of starvation. Once famine is declared it means people have already died," she said.
Five million people in South Sudan don't have enough to eat and humanitarian groups are warning that an entire generation is at risk.
Seventy per cent of South Sudanese children have never been to school and many that do attend are too hungry to learn.
"It's very difficult when children are hungry. In the classroom, the lesson, they are falling asleep. They are not paying attention at all because their stomach is crying out for something," Father Tim Galvin said from the town of Kapoeta.
Peter Walsh, the country director for Save the Children, said the future looked dire.
"We are talking about a second generation. Following the war with Sudan we spoke of this lost generation that never had the opportunity to learn," he said.
"Well, unfortunately it's happening all over again in South Sudan."
Ms Teny said the South Sudanese community in Australia also needed to start reconciling.
"You know the ruptured fabric of society at home actually spills over to the diaspora," she said.
"The diaspora actually contributes sometimes very negatively in that they use the social media and they've become what we as a party term 'internet warriors'.
"We're telling them, turn your sharp pens into sending out good, positive messages, no matter which side you are on."