|Iwata did say a new 3D Mario is in development during the Nintendo Direct held in January, but he did not say when it might be completed.|
CVG is claiming that sources have informed them Nintendo is planning on releasing a new 3D Mario game by October. During a Nintendo Direct presentation in January, Satoru Iwata did announce that the company is working on such a game and would have a playable build at this year's E3, but he gave no indication of when it might be ready for release.
It should be noted that Iwata recently told investors the Big N has some big releases planned "during the next several months," and he gave a list of said titles which includes a Mario game. Take a look:
Based on the strong lineup of upcoming software titles for both the Nintendo 3DS and Wii U systems, Nintendo expects to return to Operating Income profitability by the end of the current fiscal year. During the next several months, Nintendo expects to launch new titles in the Mario Kart (Wii U), Super Mario Bros. (Wii U), Wii Fit (Wii U), Pikmin (Wii U), The Legend of Zelda (Wii U and Nintendo 3DS), Mario & Luigi (Nintendo 3DS) and Pokémon (Nintendo 3DS) franchises. These games, along with titles from Nintendo’s third-party publishing partners, will help drive hardware momentum and introduce new audiences to the Wii U and Nintendo 3DS platforms.As you can see, he referred to a "Super Mario Bros." game on the Wii U, but as many have pointed out, he may have been referring to the New Super Luigi U DLC for New Super Mario Bros. U. Seeing as how E3 is just around the corner, we should know soon enough.
-Satoru Iwata, Global President of Nintendo