SAN FRANCISCO (AFP) - A pair of influential US film industry organisations on Wednesday put out word that movie theatres should ban smart watches or eyewear that could be used to record movies.

The Motion Picture Association of America and the National Association of Theatre Owners updated a film-theft prevention policy to recommend zero-tolerance when it comes to movie goers wearing "intelligent" devices with video-recording capabilities.

Best practices guidelines, which theatre operators are free to embrace or ignore, were modified to say that "wearable devices" as well as smartphones must be "turned off and put away at show time."

The two associations did not specifically mention Google Glass or any other gadget in the policy update released after an anti-piracy joint task force meeting at an annual ShowEast gathering of theater owners in Florida.

"Individuals who fail or refuse to put the recording devices away may be asked to leave," the policy stated. "If theatre managers have indications that illegal recording activity is taking place, they will alert law enforcement authorities when appropriate."

Google Glass - hotly anticipated by some, feared by others - became available in the United States in May to anyone with US$1,500 (S$1,906) to spare and a desire to become an "explorer."

Google has been working to burnish the image of Glass, which has triggered concerns about privacy since the devices are capable of capturing pictures and video.

Glass connects to the Internet using Wi-Fi hot spots or, more typically, by being wirelessly tethered to mobile phones. Pictures or video may be shared through the Google Plus social network.