A 'new' security robot announced by leading Japanese company Hitachi actually appears to be a four year-old American-developed product, a US robotics company has claimed.

In a statement issued today, US-based MobileRobots Inc said that the Hitachi robot is "suspiciously similar" to its own Pioneer-DX which went on sale in 2002.

"We have no problem with customers using our robots to prototype; that's what they're for. But it would be misleading to portray robot technologies we've sold commercially for four years as something new and revolutionary," said Dr William Kennedy, co-founder of MobileRobots.

The US company confirmed that Hitachi had purchased Pioneer-DX robots from its agent in Japan. MobileRobots also published an image on its website showing how its robot would fit inside the spherical white shell of Hitachi's invention.

Parts of the two products appear extremely similar, although the Hitachi robot features a camera mounted on a mast which is not present in MobileRobots' images of its product.

MobileRobots did not say whether Hitachi might have rewritten the controlling software of the robot, or added additional hardware.

Hitachi's half-metre tall robot attracted considerable attention from media and blogs after the company announced it on 7 March.

The Japanese company "plans to sell the new robot to security companies and building management firms, among other businesses", the Mainichi Daily News reported, suggesting that this would happen within three years.