Mayor Bloomberg suggested Friday that New York City public housing residents should be fingerprinted as a way to fight crime in the system's 334 buildings.

Bloomberg, speaking on his weekly radio show, said NYCHA residents make up 5 percent of the city's population while 20 percent of New York City crimes are committed in public housing.

"The people that live there, most of them, want more police protection... If you have strangers walking in the halls of your apartment building, don’t you want somebody to stop and say, ‘Who are you? Why’re you here?’"

"What we really should have is fingerprinting to get in," he went on. "And of course ... there’s an allegation that some of these apartments aren’t occupied by the people who originally have the lease."

Bloomberg and the show host were talking about a judge who ruled this week that the NYPD's stop-and-frisk tactic is unconstitutional and assigned a monitor to oversee the development and implementation of reforms.

The same judge, Shira Scheindlin, is said to be ready to take up a case about police stops in public housing.

Several Democratic mayoral candidates blasted the mayor for the suggestion to fingerprint residents.

"Disrespectful. Disgraceful. No other words apply," former Comptroller Bill Thompson said in a statement. "Just like stop and frisk, this is another direct act of treating minorities like criminals."

Bill de Blasio, the city's public advocate, called it "outrageous and insulting."

"Once again, Mayor Bloomberg has resorted to presuming innocent people are guilty simply because they happen to live in certain areas, and in doing so he is stigmatizing entire communities."