The two-year multinational probe was conducted by, The Sentry, an independent monitoring group co-founded by Clooney, and US author and peace activist John Prendergast.
Investigators tracked social media accounts, legal records, financial statements and shipping documents.
They also used satellite imagery to gather and analyse data about those funding, and profiting from the conflict.
They claim to have uncovered a network of senior officials linked to international facilitators and enablers, including bankers, arms dealers and businessmen - links claimed to extend all the way to Australia.
Researchers travelled to Adelaide and Melbourne, where a number of people were interviewed, many under the condition of anonymity.
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They also interviewed experts and eyewitnesses in Addis Ababa, Kampala, Juba, Cairo and Nairobi.
Details of their findings will be revealed at a press conference in Washington DC next week.
The newly-independent country of South Sudan has been mired in conflict since 2013, after political rivalry between forces loyal to President Salva Kiir and his rival, Vice-President Riek Machar, exploded into violence.
Thousands have been killed and displaced, with both sides accused of atrocities.
Australia is home to one of the largest diaspora of South Sudanese refugees in the world, with around 30,000 expatriates living here.
Many have active links to political parties in South Sudan.
Last year, SBS revealed that dozens of Australian-South Sudanese people had returned to their homeland to fight, for both government and opposition forces.
The groups aimed to focus global attention on ending mass atrocities around the world.
Not On Our Watch was founded by Clooney and actors Don Cheadle, Matt Damon and Brad Pitt, as well as US Ambassador David Pressman and late Hollywood producer Jerry Weintraub.
