The soldier who led a coup that ousted Mali's government and paved the way for a sweeping Islamist offensive has been promoted, the government said Wednesday, days after a new president emerged to lead the troubled nation.

Captain Amadou Sanogo led a group of fellow mid-level officers to overthrow then-president Amadou Toumani Toure on March 22 last year, upending what had been considered one of west Africa's flagship democracies.

"Today, the cabinet approved the nomination of Captain Amadou Sanogo for the grade of Lieutenant-General," a defence ministry spokesman told AFP, just two days after Ibrahim Boubacar Keita emerged from nationwide polls as Mali's president-elect.

The mutiny precipitated the fall of northern Mali to Islamist militants linked to Al-Qaeda but a military intervention by French and African troops in January chased the rebels from the region's main cities.

The coup also deepened a schism in the army between the Red Berets, loyal to Toure, and the Green Berets, who were broadly pro-junta, and Sanogo was implicated in the disappearances of Red Berets after a failed counter-coup on April 30 last year.

Human Rights Watch described his promotion as a "shameful act".

"Captain Sanogo should have been investigated for his alleged involvement in torture and enforced disappearances, instead of being rewarded by way of this promotion," said Corinne Dufka, a senior researcher for the organisation.

Once a US-trained English instructor to his fellow Malian officers, Sanogo comes from Segou, Mali's third-largest city on the Niger River and 240 kilometres (150 miles) from the capital Bamako.

His army career saw him make his way through a military academy in Kati outside Bamako, whose barracks became the junta headquarters.

Sanogo's coup was sparked by soldiers' anger over their rout at the hands of well-armed Tuareg rebels seeking independence for their homeland in the north.

Demoralised and under-equipped, the mutineers slammed Toure's regime for its incompetence in the face of the rebellion by the disenfranchised desert nomads, which has simmered for decades.

Sanogo, with a green beret perched on his shaved head, slightly pockmarked cheeks and a hoarse, raspy voice, promised in several television appearances to hand power to a civilian government.

Two weeks later he signed an agreement with mediators from the ECOWAS regional bloc to put in place an interim government, and Dioncounda Traore was appointed as its president.

But his retreat appeared to be a facade as he continued to order arrests of politicians, journalists, soldiers and those seen as close to the former regime.

As Bamako remained fragile in the wake of the coup, the Tuareg, allied with Islamists, seized the northern triangle of the bow-shaped nation, an area larger than France.

However the unlikely alliance between the secular separatists and the Islamists crumbled and the Tuareg were driven out of key positions, leaving the vast arid zone in the hands of extremists who imposed a brutal interpretation of sharia Islamic law.

Citizens were flogged, had their hands amputated and were stoned to death as punishments for alleged transgressions.

In a statement published in the French daily Le Monde in October, Sanogo compared ousted leader Toure to French general and discredited war hero Philippe Petain who was imprisoned for treason by De Gaulle.

"I have only been to Mali what De Gaulle was to France," said Sanogo.

In May last year, Sanogo and his former junta were granted a general amnesty and the captain received the status of former head of state and all the accompanying benefits, as mediators attempted to clear a political logjam.

A month later this status was withdrawn, but Sanogo was appointed as head of a committee on army reform, a post created for him as an incentive to accept a transitional government tasked with steering the country to Sunday's election.

Official results from the nationwide vote have not been announced, but Somaila Cisse, the main rival to 68-year-old Keita, congratulated him on his victory late Monday as Keita took a commanding lead.

The government is expected to make public Thursday the result of the run-off vote, called after none of the 27 candidates in the first round on July 28 secured an outright majority.