The patch prevents players from exploiting shortcuts on 'Wuhu Island Loop', 'Wuhu Mountain Loop' and 'GBA Bowser Castle 1' when playing online.
The update can be downloaded from the Nintendo eShop today, provided players have performed the latest system update.
Failure to install the patch will see players unable to participate in online races, although the single-player and local multiplayer portions of the game will remain functional.
Mario Kart 7 was voted the best game of 2011 in Digital Spy's end of year reader poll.
The game was also the fastest-selling Mario Kart title in history, and one of the first Nintendo 3DS games to sell more than one million copies in the US.
> Read our review of Mario Kart 7
Watch the Mario Kart 7 TV advert below: