Nintendo is yet to confirm a release date, but it is understood that a worldwide November launch is planned.
However, sources close to the project have since told CVG that a European rollout could be pushed back to December.
Nintendo is reportedly keen to get the Wii U into North American stores in time for Thanksgiving, but is having trouble manufacturing enough GamePads to meet demand.
The Wii U GamePad incorporates a 6.2", 16:9 aspect ratio LCD touch screen, which features a front-facing camera, a microphone, stereo speakers, rumble functionality, a sensor bar, a stylus and Near Field Communication support.
It weighs approximately 500g and is powered by a rechargeable lithium-ion battery.
The Wii U launch date has been the subject of much speculation since its unveiling at last year's E3 Gaming Expo.
Amazon Germany previously listed the console for a December 21 release, costing €399 - approximately £322/$506 - although it has since lowered the price.
The console has also been rumoured for a November release, through both Ubisoft at the E3 Gaming Expo and a leaked Black Ops 2 listing.
> Wii U: Digital Spy goes hands-on with Nintendo's new console - video
Watch the E3 Wii U Gamepad video below: