Manufacturers of the Taser stun gun on Monday unveiled a new handheld weapon on Monday which is capable of shocking three people without having to reload.

Arizona-based Taser International said in a statement the company's new X3 "electronic control device" was the first new handheld weapon since 2003 and featured enhanced safety details.

Taser International chief executive Rick Smith said the new multi-shot Taser would "increase officer safety through the ability to recover from a missed shot or even simultaneously stop up to three separate targets."

The company said the new weapon included a "pulse calibration system" for allowing electricity to be distributed across the outer layers of the skin of the target rather than deep into the body.

A video demonstration of YouTube showed three volunteers being floored by three successive shots before getting to their feet apparently unhurt.

Human rights activists have criticized Taser stun guns, challenging manufacturer claims that they are safe and non-lethal.

A December 2008 report from Amnesty International said 334 people had died after being shocked by Tasers between 2001 and August last year.