Nintendo Co. has issued a warning that children under the age of six shouldn’t play 3-D games on its soon-to-be-released handheld game machine, as looking at 3-D images for a long period of time can have a harmful effect on the growth of young children’s eyes.

The company posted the disclaimer at the bottom of its Japanese-language Web site promoting a three-day event in Japan where people can try its new Nintendo 3DS, due to launch Feb. 26 in Japan. It asks that 6-year-olds and those younger play games on the 3DS in 2-D mode.

“For children under the age of 6, looking at 3-D images for a long time could possibly have a negative impact on the growth of their eyes,” Nintendo said on the Web site. It also warned that users should take breaks every 30 minutes when playing games in 3-D and stop playing immediately if feeling ill.

The Nintendo 3DS is the company’s most-anticipated video game hardware product since the Wii home console in 2006. The new handheld device will allow users to play 3-D games without special glasses to create the illusion of depth.

The warning is similar to those made by other makers of 3-D consumer electronics products. Samsung Electronics Co., Sony Corp. and Panasonic Corp. all provide warnings on their Web sites about the possible risks of viewing 3-D images for children younger than 6 years old.

Most 3-D technologies create the illusion of depth on a flat screen by presenting different images to the left and right eye, typically using special glasses. But Nintendo is offering that effect with the display alone, a technology called autostereoscopic 3-D.

The 3DS comes with a slidebar to allow the user to adjust the level of 3-D effect on the games played on the machine.