"I want to sincerely advise all of you — those of you who have money outside the country — you bring your money back to this bank," Kiir said at the launch ceremony, at the Central Bank of South Sudan, attended by ministers and top government officials.
"I know people have very huge accounts outside the country. You repatriate this money," he added, in a short speech, before changing some of his personal cash into South Sudan pounds.
The exchange rate with the former currency, the Sudanese pound, has been fixed at one to one.
International Crisis Group warned in April, three months before the oil-producing country on July 9 declared formal independence from the north, about the potential for the large-scale diversion of state revenues for the personal enrichment of individuals in positions of power.
Each note of the country's new currency carries the head of John Garang, the rebel leader who died just months after signing the 2005 peace accord that ended Africa's longest-running conflict and paved the way for nationhood.
The central bank governor, Elijah Malok, said that Garang's image was a "mark of respect" for him and for the country's history. Malok appealed to the governors of South Sudan's 10 states to work with a technical committee, composed of bank and finance ministry officials, to ensure the swiftest possible circulation of the new money, to avoid the country being flooded with old Sudanese pounds.
"The danger is ... if we don't change quickly and it is still a legal tender in the north, a lot of money will pour in and destroy our economy," he said.
The Sudanese pound could be withdrawn from circulation within three months, he added.
The new nation's launch of its own currency earlier than expected added urgency to a dispute over what to do with the 1.5 to 2 billion Sudanese pounds in circulation in the South.
The move was complicated by Sudan's announcement that it would also launch a new currency, which the country's central bank governor described as a "precautionary measure" to protect Sudan's economy.
