Online retailers GAME, Play.com and Gamestation have admitted they will struggle to cope with Grand Theft Auto IV demand when it is released on 29th April.

Limited Edition copies are still promised for delivery on launch day, but those of you after the standard version may face a wait if you haven't pre-ordered already.

"We cannot guarantee delivery on the day of release for orders placed on or after the 7th of April," states GAME on its website, while rival Play.com offers, "we are currently sold out of this item. All orders will be dispatched on a first come, first served basis."

Gamestation too, indicates that "due to unprecedented demand for the standard editions of Grand Theft Auto IV, we are no longer taking pre-orders for this version."

The Rockstar creation is expected to be one of the biggest games released this year, with some predicting it will top six million units in its first week of sale.

The retail community has been offering plenty of incentive to pre-order the title, with GAME giving away 500 free Microsoft Points to users, while HMV doubled that offer to 1000 Points as well as a book of vouchers worth GBP 130.

April and May could be massive sales months for the industry this year - as well as GTA IV, April will also see the release of Wii Fit from Nintendo, and Rock Band from EA, which was dated and priced for release today, is due out next month.