It looks as if Wii Fit is well on its way to becoming the fastest selling Wii game ever with retailers telling Games Dog that Friday was a blockbusting day for the new fitness game.

Since its launch in Japan on 1 December 2007, Wii Fit has already sold in excess of 1.4 million units to date, making it one of the fastest selling Wii titles in Japan.

Here in the UK, it has already outstripped all previous records on Play.com by selling out the entire pre-order allocation in one day leaving the online retailer "overwhelmed" by demand.

A spokesperson for the DSG group, that includes Currys, PC World and Dixons.co.uk, told Games Dog that they were selling a copy of Wii Fit every 4 seconds on Friday, with some stores now sold out of the game.

An Amazon.co.uk spokesperson also informed us that Wii Fit has proved "wildly popular" and their stock was sold out within 24 hours. Although they would not release exact figures they said the sales levels were "unprecedented for a fitness product".

>> Reviewed - Wii Fit
>> News - Wii Fit national tour