Gun? Check. Nightstick? Check. Hand sanitizer? Huh? New York's Finest have been given a new weapon to combat criminal scum — "mobile hand sanitizers."

The NYPD has begun distributing "personal protective" liquid-sanitizer dispensers that clip to the belts of beat cops and school-safety officers, according to a Jan. 22 department order obtained by The Post.

"A police precinct is like a petri dish, with all the cops coming from the street with every bacteria," said a cop in lower Manhattan.

The earnest-sounding memo introducing the new "optional" equipment advises cops to be careful not to hook the mini-bottles onto their firearm trigger guards, radio antennas and expandable batons.

And cops are in serious trouble if they lose their germ-killing goop, the memo warns.

The dispensers can be replaced only after cops write a report on "typed letterhead" signed off by their commanding officer.

When soap and water aren't available, fastidious crime fighters can use the alcohol-based sanitizer "as often as needed" and refill them at any precinct station house.

"Commanding officers will ensure an adequate supply of sanitizer is maintained to refill," the memo instructs.

"The reason why they are doing this is because so many cops were already walking around with Purell," the cop said. "When I first started, I would always get sick until I started using it."

Primarily used to prevent the H1N1 virus, hand sanitizers are also effective against bacteria and other viruses. Up to 80 percent of all infections get spread by hands, according to the Centers for Disease Control and Prevention.

But the sanitizer will crowd an already cumbersome utility belt for cops. With handcuffs, keys, radio, bullets, pistol, pepper spray, flashlight and baton, the belts weigh 16 pounds.