Mali's government has created a body to open talks with Islamist militants whose insurgency has made vast portions of the country ungovernable, the interim prime minister said on Friday, in the face of objections by France.

A year ago ousted former president Ibrahim Boubacar Keita said his government was prepared to negotiate with al Qaeda-linked militants. National talks in the aftermath of the August coup that overthrew Keita endorsed that policy.

"Dialogue is not an exclusive solution, but rather an additional means of bringing back into the bosom of the Republic those who left it, often for existential reasons far removed from any fanaticism," said interim Prime Minister Moctar Ouane.

The statement did not provide details of the makeup of a negotiating body.

Former colonial power France, which has 5,000 troops in Mali, has previously signalled opposition to negotiating with Islamist groups that did not sign a 2015 peace deal it considers a framework for restoring peace to northern Mali.

France is searching for an exit strategy after getting bogged down in a counter-insurgency operation in the Sahel which has cost billions and seen 55 French soldiers killed.

The violence is persisting with signs it is spreading to coastal West Africa.

Chad will deploy some 1,000 troops to the tri-border region of Niger, Burkina Faso and Mali to reinforce national armies, sources said last week.