BANGKOK — Tobacco giant Philip Morris and more than 1,400 Thai retailers will sue Thailand's health ministry over a rule that would nearly cover cigarette packets with smoking warnings, a tobacco trade representative said Wednesday.

The regulation scheduled to take effect Oct. 2 requires that 85 percent of space on the packets' front and back be dedicated to warning messages and images, some containing graphic pictures of lung cancer patients.

Varaporn Namatra, executive director of the Thai Tobacco Trade Association, said the organization and Philip Morris (Thailand) will file a lawsuit to the Administrative Court to invalidate the decision by July 4.

"Given the fact that Thailand already has some of the biggest health warnings in the world, TTTA can't see why the new requirement is necessary, especially when it will just complicate the work and create additional problems for so many hard-working retailers," Varaporn said.

She said the higher costs could cause consumers to turn toward cheaper, lower-margin tobacco that is not subject to the new warnings.

Thailand and Australia are among the countries with the largest anti-smoking pictorial health warnings in the world. Australia also bans cigarette companies' logos and colors. The U.S. Food and Drug Administration had planned to require large and often graphic warning labels on cigarettes, but it is redesigning the labels after a court ruled against its plan.

Under the Thai Public Health Ministry's current regulations, warning messages take 55 percent of space on the front and the back sides of the packets.

Deputy Public Health Minister Cholnan Srikaew said the larger warnings will be more effective in deterring smoking.

"The existing warnings have not really yielded visible results in decreasing the number of smokers, so we need to make them bigger," Cholnan said.

The Public Health Ministry said about 50,000 people die from smoking-related diseases each year in the Southeast Asian nation of about 65 million people.