French President Francois Hollande said Saturday that it was up to the community in Africa to decide how and when to intervene militarily over the Islamist occupation of northern Mali.

"For an intervention in the framework of the African Union and the United Nations to take place, it's up to Africans to determine the moment and the force," Hollande said during a televised interview on Bastille Day.

"We must show solidarity. At the Security Council, there is a resolution which would enable precisely that intervention to be made with the backing of the UN."

Speaking in Addis Ababa on Saturday, the head of the AU Commission Jean Ping told a closed-doors meeting of heads of state the situation in Mali was "one of the most serious situations our continent is confronted with."

"The environment created in north Mali has become a refuge for terrorist groups... which constitute a serious threat to regional peace and security and international peace and security," Ivory Coast President Alassane Ouattara, chair of the AU Peace and Security Council, also warned.

Al-Qaeda-linked Islamist fighters took advantage of the chaos following a military coup in the west African nation to seize key towns in the north. The jihadists have ousted rival Tuareg separatist rebels, enforced strict Islamic law and destroyed ancient World Heritage sites they consider idolatrous.

West African group ECOWAS has said it is ready to send about 3,000 troops to help restore order in Mali if it has UN backing. But Mali must first form a legitimate government in the wake of the coup.

Mali's Prime Minister Cheick Modibo Diarra arrived in Paris on Friday to announce the formation of a representative government to President Dioncounda Traore, who is in France for medical treatment.

Mali government spokesman Hamadoun Traore told AFP the two men would meet for talks on Saturday afternoon.

"They will discuss the military option. It is a matter of restoring the country's sovereignty," he said.

Earlier Saturday French Defence Minister Jean-Yves Le Drian said the formation of a working government was essential.

"It is necessary to have a national unity government in the capital to ensure the calmness that is needed, that is essential, to win back territorial integrity," he said.

"It is very complicated, it could be very serious for the future, because there are significant terrorism risks. But the African presence is essential, with the support of France and Europe obviously," Le Drian said.