Mutō believes that the Organising Committee's latest projected costing of ¥600 billion (£4.3 billion/$5.6 billion/€5 billion) will be completely balanced.

He said that none of the budget will come from the public purse and will be fully covered by ticket sales, sponsorship and marketing revenue, as well as contributions from the International Olympic Committee (IOC).

It follows an announcement earlier this week of planned cost allocations shared between the Organising Committee, the Tokyo Metropolitan Government (TMG) and other national and regional authorities.

Under the latest projections, which have been drawn-up by Tokyo 2020 and the TMG and have not yet been formally ratified, the Summer Olympic and Paralympic Games will cost a total of ¥1.40 trillion (£10 billion/$12.9 billion/€11.4 billion).

The TMG would also spend ¥600 billion while the National Government would contribute ¥145 billion (£1.1 billion/$1.4 billion/€1.2 billion).

The remainder consists of the cost of transportation and security measures around venues within the related local municipalities.

"While aiming at reducing even more the overall budget, this new framework lowers the proportion of public money being invested to organise the Games and increases the proportion of private money being used," Mutō told insidethegames.

"Therefore, the Organising Committee budget now amounts to ¥600 billion, requiring an extra ¥100 billion (£705 million/$902 million/€800 million) in revenue for a balanced budget."

He added: "I'm very confident that we will be able to secure this extra-funding as our commercial programmes - particularly in sponsorship sales - have met with unprecedented success. 

"It is important to remember that the Organising Committee budget is purely composed of private money which includes the IOC's contribution, ticket sales, Tokyo 2020 sponsorship, merchandising and other marketing programmes."

Tokyo 2020 unveiled a budget of between ¥1.6 trillion (£11 billion/$13.6 billion/€13.1 billion) and ¥1.8 trillion (£12.4 billion/$15.3 billion/€14.7 billion) in December.

This includes a "contingency budget" of up to ¥309 billion (£2.2 billion/$2.8 billion/€2.5 billion) not included in the latest projection, however, which explains the difference.

Tokyo 2020 have been angered by comments made by Shinichi Ueyama, a Japanese public policy expert who led a TMG probe into costings.

He told Associated Press that, in general, numbers in Olympic bidding files are "almost complete fiction" and warned that the burden on taxpayers could be twice as high as initial estimations.

In September, a task force, appointed by Tokyo Governor Yuriko Koike, warned that drastic changes must be taken to avoid the overall Games budget ballooning to ¥3 trillion (£21.1 billion/$27.1 billion/€24.2 billion).

A working group was subsequently set-up to find ways to trim the budget and avoid this happening.

Ueyama has previously blamed the rising budget on "poor supervision" and a "lack of clear authority".

It comes after a far lower budget of just ¥730 billion (£5.1 billion/$6.6 billion/€5.9 billion) was put forward during Tokyo's successful bid for the Games in 2013.

"The Tokyo 2020 Organising Committee has been working closely with every stakeholder to make last Wednesday's landmark agreement come true," Mutō added to insidethegames.

"Over the last few months, the Organising Committee with the TMG, the Japanese Government, and with local Governments of the seven prefectures and four other cities hosting events, together researched innovative ways to control costs and to agree on the allocation of costs.

"After long and sometimes intense discussions, I am delighted that everyone agreed an overall approach governing the division of roles and the allocation of costs for the Tokyo 2020 Games."

IOC Evaluation Commission chair Patrick Baumann claims they have no concerns over the proposed budgets put forward by 2024 Summer Olympic and Paralympic Games contenders Los Angeles and Paris.