NEW YORK -- A smokers' advocacy group says it has sued New York City seeking to overturn the city's ban on electronic cigarettes.

The NYC Citizens Lobbying Against Smoker Harassment announced the lawsuit Tuesday.

The Smoke-Free Air Act was signed into law in December, Mayor Michael Bloomberg's last month in office. It prohibits e-cigarettes in all areas where regular cigarettes are banned.

The lawsuit says regulating both tobacco smoke exposure and e-cigarettes violates the "One Subject Rule" of the city's charter.

The FDA plans to regulate e-cigarettes but has not yet issued proposed rules.

City Council spokeswoman Robin Levine says the legislation protects the public from "unregulated substances." She says the council is confident the courts will uphold it.

The city's Law Department says it will review the complaint when it is served.