Tokyo 2020 chief executive Toshirō Mutō has dismissed a study by Oxford academics on the cost of the Olympics.
The paper suggested Tokyo 2020 would be the most expensive Games in history, putting the cost at $15.84 billion (£12.25 billion/€13.34 billion).
This does not include the financial impact of the postponement of Tokyo 2020 until 2021, caused by the coronavirus pandemic.
Speaking after the latest meeting of the Tokyo 2020 Executive Board, Mutō rejected the claims.
"There are no financial grounds for the numbers revealed in that report," he said, as reported by Reuters.
"I am not in a position to make a comment on that currently – I am simply confused by this."
The last budget given by Tokyo 2020 was in December 2019 and put the cost at $12.6 billion (£9.8 billion/€10.6 billion).
The International Olympic Committee (IOC) has already said the postponement will cost them around $800 million (£620 million/€670 million), while Japanese organisers have yet to announce what their share will be.
Simplification measures are being discussed to reduce the cost of the Games, including those relating to the number of people involved, infrastructure and Ceremonies.
The exact cost of the items will not be available until December.
The 39-page study - Regression to the Tail: Why the Olympics Blow Up - was carried out by academics at the University of Oxford and headed up by Professor Bent Flyvbjerg.
It focused on the sports-related costs of hosting the Games, excluding transport and tourism infrastructure that is often lumped in, and found that "every Olympics since 1960 has run over budget".
It notably suggested that the IOC should be obliged to cover 10 per cent of any Olympic Games cost overrun, arguing that currently "there is little alignment between incentives to keep costs down and making decisions about cost".
The IOC has been critical of the paper, however, claiming that it took a "fundamentally flawed approach" by mixing the budget for the organisation of the Games and the infrastructure budgets of the host city, region and country.
Flyvbjerg has since written to IOC President Thomas Bach with a point-by-point rebuttal of criticisms of the paper.