The ministers responded to a request from the Iraqi government "to provide gendarmerie training to complement the military training," said NATO spokesman James Appathurai.
The paramilitary training is due to begin in September, with about 50 extra NATO personnel deployed to the alliance's training center in the outskirts of Baghdad.
"The goal is to create a well-trained cadre for each of the eight Iraqi national police brigades," he told reporters. "It will emphasize ethnic and religious tolerance."
NATO launched its military training mission in 2005 with about 170 staff.