Wii gamers in Japan could be out-flabbing their friends with a new multiplayer version of Wii Fit later this year, according to Japanese newspaper the Nikkei business daily. Wii Fit Plus will apparently allow users to compete with others over the Internet, in a variety of activities. The Nikkei also revealed that a new Mario game could hit Japanese shelves in the second half of 2009.

Reuters posted up an article earlier today about the Nikkei’s claims, which were not attributed to any source at Nintendo. However, the news seems to back up previous rumours - especially Nintendo asking retailers to save some space on their shelves this Christmas for a ‘big release’. Presumably that would be Mario and not Wii Fit, which is generally played once or twice before being stashed under a bed or on top of a cupboard.

While these release estimates are for Japan, if true,  it’s very likely that a new Mario game will be released in the US and Europe at the same time. Wii Fit Plus is expected to hit Japan in the fall.

More details on both of these titles are expected to be announced at E3.