* Argue act hurts right to communicate with adult smokers
* Lawsuit filed in federal court in Kentucky (Adds legal analyst comment, byline)
By Brad Dorfman and Jonathan Stempel
CHICAGO/NEW YORK, Aug 31 (Reuters) - A group including some top U.S. tobacco companies filed a federal lawsuit on Monday to block provisions of a new tobacco law, arguing it violated their free speech rights under the U.S. constitution.
R.J. Reynolds Tobacco Co, a unit of Reynolds American Inc RAI.N that makes Camel and Winston cigarettes, and Lorillard Inc LO.N, which sells the Newport menthol brand, were among those seeking to void parts of the law.
Altria Group Inc (MO.N), which makes Marlboro cigarettes and is the largest U.S. tobacco company, is not involved in the case after breaking with rivals to support the law.
The legislation signed on June 22 gives the Food and Drug Administration broad powers for the first time over cigarettes and other tobacco products [ID:nN22512674].
It calls for larger warnings on cigarette packages, restricts vending machine sales, bans most flavored products and curbs print advertisements targeting children. The FDA also has final say over new products and marketing claims such as "light" and "low tar."
While not challenging the FDA's authority to regulate tobacco products, tobacco companies say the law goes too far in limiting their commercial speech rights in light of existing bans on television and radio advertisements.
"Even prior to the act, plaintiffs had few avenues of communication for speaking to their adult consumers," the companies said in the lawsuit filed in a federal court in Kentucky. "The act imposes sweeping and unprecedented restrictions that effectively foreclose those avenues of communication that remain."
The companies are asking the court to overturn bans on the warning labels, using color and graphics in labels and advertising, some outdoor advertising and sponsorships of sporting and other events.
While commercial speech has less constitutional protection than other speech, the government still faces a high hurdle in trying to restrict it, legal experts said.
"The Supreme Court has rejected the rationale that it is okay to ban tobacco advertising to protect children," Eugene Volokh, a professor at UCLA School of Law in Los Angeles.
"It has generally held that for advertising of products not legal for children, such as alcohol and tobacco, we cannot just say, 'children may see an ad and therefore try to get the product illegally.'"
Proponents said the FDA legislation would help curb youth smoking, but legal experts have questioned whether that would make the restrictions legal.
Even one opponent of the tobacco industry said the companies could have a good case.
"The tobacco companies have a very legitimate claim based on the Supreme Court's own rulings," Michael Siegel, professor of community health sciences at Boston University's School of Public Health.
"I question why the crafters of the legislation did not deal with the First Amendment issue appropriately," he added. "A ruling for the companies would negate a good portion of this legislation."
Edward Sweda, chief attorney for the Tobacco Products Liability Project at Northeastern University School of Law in Boston, said the tobacco companies already agreed to some advertising restrictions as part of a landmark legal settlement with U.S. states in 1998.
"I am highly doubtful that the Reynolds, Lorillard lawsuit will be ultimately successful," he said.
Other plaintiffs in the lawsuit include cigarette maker Commonwealth Brands Inc; tobacco retailer Discount Tobacco city & Lottery Inc and National Tobacco Co.
A representative for the FDA said the agency does not comment on pending lawsuits.
The case is Commonwealth Brands Inc vs. United States, U.S. District Court, Western District of Kentucky (Bowling Green), No. 09-117. (Additional reporting by Susan Heavey in Washington, D.C.; editing by John Wallace and Andre Grenon)