A hacking group behind a Nintendo Wii modification chip that allows the family machine to play copied software claims to have finally cracked the Wii U too.

WiiKey has started to offer the WiikeU on its website, an optical drive emulator that allows you to play Wii U and Wii games stored on any USB device rather than needing the original disc. That essentially means you can copy any disc to a USB stick or portable HDD, not necessarily one that you own yourself.

"Yes, its real - we have now completely reversed the WiiU drive authentication  disk encryption, file system, and everything else needed for this next generation K3y," the group says.

Nintendo disagrees. "Nintendo is aware that a hacking group claims to have compromised Wii U security," it told gaming site Eurogamer. "However, we have no reports of illegal Wii U games nor unauthorised applications playable on the system while in Wii U mode.

"Nintendo continuously monitors all threats to its products' security and will use technology and will take the necessary legal steps to prevent the facilitation of piracy."

If the WiikeU is genuine and does work, it would be a further blow to a company that has already had to readjust its targets for the games console that launched at the tail end of last year. WiiKey also claims that its new product works globally, across all regions, which is an additional cause for concern.