South Sudanese President Salva Kiir, in a June letter to civil servants, said an estimated $4 billion was missing from federal coffers.
The country is one of the poorest in the world and revenues were curtailed after oil production was halted in January because of a dispute with Sudan. Sudan's inflation rate has soared since the beginning of the year, prompting the government to consider austerity measures.
An audit of South Sudan's finances found billions of dollars of tax revenue went unaccounted for through elevated payrolls and unmonitored contracts, the independent Sudan Tribune reports.
"These contracts were single sourced, not vetted by the Ministry of Legal Affairs and Constitutional Development," the audit read. "Payments were released on the orders of the implementing agencies even before commencement of work."