French forces have freed a Dutch man held hostage in Mali since 2011 by al Qaeda's north African arm, the French defence ministry said.

It said Sjaak Rijke, who was kidnapped in Timbuktu in November 2011, was freed this morning during a special operation and had been transferred "safe and sound" to a temporary base in Tessalit, north-east Mali.

French forces killed two militants and captured two others during fighting that took place during the early morning operation, said Lieutenant Colonel Michel Sabatier, a spokesman for Barkhane, the French counter-insurgency operation in the region.

Dutch Foreign Minister Bert Koenders said Rijke was in good condition considering the circumstances and receiving medical treatment under Dutch supervision.

"The liberation of Mr Rijke underscores France's staunch determination to fight armed terrorist groups in the Sahel region as part of the Barkhane operation," the French ministry said in a statement.

In November Rijke's captors, the al Qaeda-affiliated AQIM group, issued a video of him along with French national Serge Lazarevic.

Lazarevic, held captive in the Sahara for three years, was released the following month in exchange for four Islamist militants with ties to al Qaeda in north Africa.

France launched an intervention against al Qaeda-linked militants in its former colony Mali in January 2013.

It has since created Barkhane, a 3,000-strong counter-insurgency force to track down Islamist militants, including AQIM, across a band of the Sahara desert stretching across five countries from Chad in the east to Mauritania in the west.

Dutch troops have been deployed in Mali as part of security and peacekeeping missions under the aegis of the United Nations.