Ly, a 49-year-old career technocrat and the son of a celebrated writer, was until recently an adviser to the governor of the Central Bank of West African States (BCEAO), based in the Senegalese capital Dakar.

He has little political experience and is expected to rely heavily on advisers as he begins the task of appointing a cabinet to return stability to a country upended by a military coup and Islamist insurgency last year.

Born in Paris, Ly gained France's highest teaching diploma from the prestigious Ecole Normale Superieure de Lyon, a masters degree in economic history from the Sorbonne and a diploma from ESSEC, one of Europe's top business schools based near the French capital.

He began his career at the World Bank before moving via the general secretariat of the president of Mali to an analyst role at the BCEAO in 1994.

He was given the role of director of studies at the bank and rose to the position of chief financial officer, a post which he held for six years before he was promoted to national director for Mali and then adviser to the governor.

Ly is the son of the late novelist and political activist Ibrahima Ly, who fled Mali after spending time in jail and complaining of being tortured under the regime of Malian military dictator Moussa Traore.

The new premier's mother, Madina Tall Ly, served as an ambassador under Alpha Oumar Konare, president of Mali during most of the 1990s.

Ly pipped a number of more obvious choices, including Tieman Coulibaly and Soumeylou Boubeye, both recent foreign ministers.

Central bank sources in Dakar told AFP Ly had resigned "a few days ago" while Malian newspapers reported that he had greatly increased his journeys between Bamako and Dakar in recent weeks.

The main task ahead of Ly, a close confidant of Keita, will be to make good on the president's pledge when he was sworn in on Wednesday to unite Mali and end endemic corruption.

Mali's constitutional court confirmed Keita's landslide victory three weeks ago in the August 11 presidential run-off after an election campaign focused on law, order and ending the culture of impunity in public office.

"I want to reconcile hearts and minds, restore true brotherhood between us so that all the different people can play their part harmoniously in the national symphony," Keita said.

His election in the first presidential polls since 2007 was seen as crucial for unlocking more than $4 billion in aid promised by international donors who halted contributions in the wake of the coup.

Army officers angry at the level of support they had received to combat a separatist Tuareg rebellion in Mali's vast desert north overthrew the democratically-elected government of President Amadou Toumani Toure on March 22, 2012.

In the chaos that followed, the Tuareg seized control of an area larger than France before being ousted by Al-Qaeda-linked groups who imposed a brutal interpretation of Islamic law on the local population, carrying out amputations and executions.

Their actions drew worldwide condemnation and prompted France to launch a military offensive at Mali's behest to oust the Islamists in January.

The country's return to democracy has allowed France to begin withdrawing some of the 4,500 troops it had sent in.

Ly's in-tray over the coming months will include tackling an economy battered by conflict, as well as healing ethnic divisions in the north and managing the return of 500,000 people who fled the Islamist insurgency.

Corruption has tainted government institutions and the military in Mali since it gained independence from France in 1960 and the country remains in the bottom third of Transparency International's Corruption Perceptions Index.

A 2012 report by the Washington-based think-tank the Carnegie Endowment for International Peace Foundation spoke of "state complicity with organised crime" as the main factor enabling the rise of armed Islamist rebel groups in the north.