The Kyoto-based video giant said the loss compared with a 2.0 billion yen loss in the same period last year.

The company suffered an operating loss of 57.3 billion yen for the first half, reversing the operating profit of 54.2 billion yen a year earlier, while sales plunged 40.6 percent to 215.7 billion yen.

"Due to re-evaluation of assets in foreign currencies, exchange losses totalling 52.4 billion yen occurred," Nintendo said in a statement.

It also said the slump was "due to a small number of hit titles overall, a decrease of both hardware and software sales" and price cuts in its 3DS handheld console as well as the Wii home video game hardware.

Nintendo revised downward its full year forecast, projecting a net loss of 20 billion yen for the 12 months to March 2012, compared with its earlier estimate of a 20 billion yen net profit.

It slashed its sales forecast for the year to 790 billion yen from 900 billion yen expected earlier, with its full-year operating profit now seen at 1.0 billion yen against a previous estimate of 35.0 billion yen.