While millions of South Sudanese face food insecurity, human rights abuses, and displacement, some of the country's political elite are alleged to have been enriching themselves.
A two-year investigation by the humanitarian organisation The Sentry claims to have uncovered evidence of high-ranking officials and those close to them amassing overseas fortunes through murky business deals and large payments from corporations.
Those alleged to be involved in questionable behaviour include South Sudan's President Salva Kiir and his deposed rival Vice President Riek Machar.
Investigators tracked social media accounts, legal records, financial statements and shipping documents.
"The evidence is thorough, it is detailed and it is irrefutable," said The Sentry's co-founder George Clooney, presenting the findings at a news conference in Washington D.C.
"It involves arms dealers, international lawyers, international banks, international real estate."
Actors George Clooney and Don Cheadle (R) participate in a news conference for the release of 'The Sentry' report on South Sudan (AAP) Source: ABACA USA
An Australian connection
Investigators travelled to Australia, home to one of the largest South Sudanese refugee diasporas in the world, in a bid to uncover the money trail.
They looked at the assets and income of some Australia-based members of the community linked to South Sudanese officials to try and determine if funds were coming from overseas to support their lifestyles.
"We met with a large group of South Sudanese people that are now living in Australia and asked them do you know where certain political elites live? Do you know their children? Do you know what they do for jobs?" said lead investigator Debra La Prevotte.
Despite a number having large homes and luxury cars she said the great majority did not appear to be employed.
"If that is the case what is the source of the money that is supporting (their) lifestyle?"
"Is Australia through their hospitality and welcoming in the displaced people of South Sudan also becoming a place where they are offshoring their money and assets?"
Investigators said they were also told that there were people willing to fly money in to Australia for the political elites, or use their own businesses to have money transferred into the country as a nominee or conduit.
The Sentry has shared its findings with several Australian law enforcement agencies and the Australian Ambassor to the United States.
Applying financial pressure
The investigation also found top officials in South Sudan could not continue to benefit from the civil conflict without the system of international banks, businesses, arms brokers, real estate firms, and lawyers who knowingly or unknowingly assist them.
In a bid to stop the war and atrocities, The Sentry is urging the international community to take action against banks that fail to stop dubious transactions, and impose asset freezes.
"We are proposing to combine anti-money-laundering measures with targeted sanctions focused on the top leaders accompanied by robust enforcement," said The Sentry's
Co-founder John Prendergast.
He said South Sudan's leaders have not taken seriously United Nations threats to impose consequences for their action, and financial measures could be more productive.
Government denials
South Sudan's Information Minister Michael Makuei Lueth has rejected the allegations.
"These reports are not based on anything. They are actually intended to tarnish the image of the president, his family and the people of South Sudan," he told the BBC.
The Executive Director of the United States-based World Peace Foundation, Alex de Waal, says George Clooney and John Prendergast were once close to South Sudan's leadership.
"Both for Prendergast and for Clooney it would be quite valid to criticise them for not having stood up (earlier)," he told the BBC.
"They were allowing the South Sudanese to get away with human rights abuses, and with corruption, and reckless political and military behaviour at a time when judicious criticism and calling them to account could have been very much more effective."
The world's newest state plunged into conflict in 2013 following a fallout between President Kiir and Mr Machar.
A peace deal reached a year ago under international pressure has been violated repeatedly by fighting.
