Wii games are played with a motion-sensing controller that is waved, swung and twisted to direct the on-screen action.
Although the controller comes with a wrist strap, reports of damage caused by snapping straps have been cropping up on video game Web sites.
There is even one site, Wiihaveaproblem.com, dedicated to chronicling tales of Wii-related carnage. On Wednesday, the site's damage toll included reports of 13 broken straps, 7 televisions and 2 laptop computers.
In an e-mail sent to Wii customers and posted on various Web sites on Wednesday, Nintendo said extreme motion could snap the strap by causing players to lose their grip on the remote.
Copies of the e-mail were posted on various sites, and a company spokesman confirmed it was authentic.
"Hold the remote securely and avoid excessive motion during game play. If your hands become moist, stop and dry your hands," the company recommended.
Nintendo also cautioned players to stay at least 3 feet away from the TV and to make sure people and objects were safely outside their range of motion.
Nintendo gives tips on safe gameplay on its Web site, at http://www.nintendo.com/consumer/wiisafety.jsp.