Mali in January called for military support from former colonial power France to fight Islamic militants. Foreign and al-Qaida fighters took control over northern Mali following a coup in early 2012.
Bloomberg News obtained a copy of a 26-page report from Ban calling on African forces to integrate into a U.N. mission that would replace French forces in Mali. A French combat and counter-terrorism role would be needed to support a U.N. mission, however.
"Given the anticipated level and nature of the residual threat, there would be a fundamental requirement for a parallel force to operate in Mali," the report said.
The United Nations said Mali needs political reforms to correspond with security gains if it's to ensure stability and territorial integrity.
Ban's report expresses concern about the residual nature of insurgents fighting against Malian and French forces, however.
"An unknown number of fighters have sought refuge outside Mali or have melted back into the population, retaining weapons caches and the capacity to re-emerge," the report warns.