The figure represents $2.2 billion (£1.7 billion/€1.9 billion) of savings from the venue master plan, with an addition $2.1 billion (£1.6 billion/€1.8 billion) cut from the operational budget for the Olympic and Paralympic Games.

It is not exactly clear how this has been achieved but Coates and Tokyo 2020 chief executive Yoshiro Muto claimed there would be more cuts as the Japanese capital continues its preparations for the Games.

Coates also dismissed concerns following a recent audit which said the total amount spent on the event by the Central and Local Governments could reach ¥3 trillion (£20 billion/$26.5 billion/€23 billion).

The figures were revealed in a survey by the Board of Audit.

The Australian insisted these were "not Games costs that Tokyo 2020 should be burdened with" as they mainly related to projects not directly connected to the Olympics and Paralympics.

Coates insist, however, that there was "more to come" from organisers in the cost-cutting department, a key aim of the IOC amid a recent apathy from city towards bidding for the Games.

Tokyo were awarded the 2020 Olympic and Paralympic Games by the IOC at its Session here five years ago, being chosen ahead of Istanbul and Madrid. 

"The International Federations all understand now the reduced scoping and they have got to play their part," Coates said.

"This is a result of increased cooperation as the other stakeholders understand the importance of producing cheaper Games."

In a report to the IOC Session here today, Muto claimed the measures implemented by the IOC will help avoid any possibility of the budget growing in the lead-up to the event.

"Agenda 2020 and the New Norm will allow Tokyo 2020 to suppress future budget increases," Muto said.

"We have reached the phase of detailed preparations."

Spiralling costs have been one of the main concerns in the build-up to Tokyo 2020 following a reluctance from cities to bid for the Games owing to the financial burden placed on them.

A revised budget of ¥1.35 trillion (£9.1 billion/$12.3 billion/€10.3 billion) was unveiled by Tokyo 2020 in December, with organisers claiming the number represented a significant reduction on previous figures.

A third budget is due to be released later this year.