Tokyo Olympic organisers said Friday they are spending 1.35 trillion Japanese yen about USD 12.6 billion to stage next year's games.
Organisers said the expenditure is unchanged from a year ago, although robust sponsorship and ticket sales have generated a contingency fund of an extra USD 300 million.
However, Japan's National Audit Board, in a 177-page report prepared for the national legislature, said next year's Olympics will cost much more than organisers say.
The audit lists an added USD 9.7 billion (1.06 trillion yen) it says are Olympic-related costs that have not been included.
In addition, the city of Tokyo has previously said it would spend another USD 7.4 billion (810 trillion yen) on Olympic-related projects.
Tokyo Governor Yuriko Koike said at the time the spending was "for projects directly and indirectly related to the games."
"It aggregated a wide range of projects that could be seen as contributing to the games, including those that were implemented without regard to the games."
The Tokyo Olympics open on July 24 and close August