In an interview with the Financial Times, Petraeus, who held a similar charge in Iraq prior to coming to Afghanistan, said he plans to expand the program, despite criticism from human-rights groups and aid agencies that the program could bring about a new generation of warlords.
The program was put in place to help Afghan forces take control of their country's security by 2014.
Petraeus says the Afghan Local Police program is critical to win local support and support those in isolated areas who want to resist the Taliban.
"The idea is that these actually mobilize not just individuals, but communities," he told the newspaper, adding the recruits work "for the district chief of police, not a local warlord or elder or power-broker."
In other comments to the newspaper, Petraeus said it is only in the past few months that the forces have gotten the inputs right for the counterinsurgency effort such as intelligence assets, military force and civilian assistance, although the war is in its 10th year.
The assessment coming in the midst of rising militant violence may, however, be another indication it may not be possible for a large reduction of forces starting in July under the drawdown program.