Retreating Islamic State terrorists are sowing yet more death in Iraq by planting mines as they flee from encroaching government forces.

The Iraqi government is taking back increasing amounts of land from ISIS, allowing Christians and others to return to their traditional terrorities on the Nineveh plains.

But schools and cities cannot be rebuilt without a massive programme to remove the many hundreds of explosive devices mined into the land, according to the head of the Chaldean Catholic Church.

Patriarch Louis Raphael I Sako said the jihadists are continuing "to sow death with mines and explosive devices" as they retreat, Agenzia Fides reports.

He said that before returning to and rebuilding "our beloved city" of the Nineveh Plain, it will be necessary to remove the mines.

Iraqi forces are expected to attempt to retake Mosul, the main ISIS stronghold in Iraq, next month. US and other humanitarian agencies are waiting in the wings to step in with the massive humanitarian aid that will be needed to help the recovery and resettlement the city after it is recaptured.

"The jihadists of Daesh, even when they pull back, they continue to sow death with mines and explosive devices," said Sako.

He has already asked the French organisation Fraternité en Irak to de-mine the first two Nineveh villages to be freed. "It is more pleasant to build schools or clinics", said Sako in his report to Agenzia Fides, "but nothing can be rebuilt if the clearing of land mines is not carried out."