A Nevada judge said Thursday that he will allow a voter-approved smoking ban to take effect in Clark County but without criminal penalties.

Clark County District Court Judge Douglas Herndon issued a preliminary injunction against part of measure that would make smoking illegal in bars and restaurants, in slot machine sections of grocery and convenience stores, and at video arcades, shopping malls, schools and day-care centers.

The judge made a distinction between criminal enforcement by police and civil enforcement by health inspectors, and declined to issue an injunction preventing individual smokers from being ticketed.

A lawyer for the Southern Nevada Health District said actual enforcement would follow a review of the judge's complex decision.

"We're going to enforce by education first," district lawyer Stephen Minagil said.

The ruling is expected to have a statewide effect well beyond the Las Vegas-area businesses that challenged the Clean Indoor Air Act.

Law enforcement and health officials in other parts of the state have said they wanted to wait for Herndon's ruling after he imposed a temporary restraining order Dec. 7. That move prevented the act from taking effect Dec. 8 in the state's most populous county.

The judge acknowledged that his ruling left unanswered key questions about the constitutionality of the measure, which was approved 54 percent to 46 percent as Question 5 on the Nov. 7 ballot.

Herndon scheduled a Jan. 23 hearing to consider a request from defendants, including state Attorney General George Chanos, to decide whether the ban passes constitutional muster — a step that lawyers on both sides say would clear the way for appeals to the Nevada Supreme Court.

"This particular initiative has problems," Herndon said, "how things are defined, what isn't defined, how it's supposed to be applied."

Opponents including southern Nevada tavern owners say the ban unfairly discriminates against certain businesses and does not make clear whether smokers or business owners should be punished for offenses.

The law still allows smoking on the gambling floors of casinos on and off the Las Vegas Strip.