While such extensive changes would be in tune with the Movement's current focus on cost-containment and sustainability, they would risk making a mockery of what was a hard-fought bidding process and enraging Istanbul and Madrid, the Japanese capital's defeated opponents.

One senior IF leader in particular has made plain to insidethegames his disgruntlement at proposed changes that could see his sport moved well outside Tokyo.

A meeting on the issue - which provides an early example of the tensions that actually trying to act on the Agenda 2020 principles is likely to give rise to - is expected to take place here later today.

Tokyo Governor Yoichi Mazusoe announced in June that venue plans for the Olympic and Paralympic Games were to be "revised" due to concerns over projected costs.

It quickly emerged that one of the plans to be reviewed would be construction of a canoe slalom course in Kasai Rinkai Park, built on reclaimed land and the focus of widespread opposition from local environmental groups.

It was also claimed that basketball and badminton could be affected.

Tokyo 2020 is set to look very different when its successful bid, when they beat Istanbul and Madrid at the 2013 Session in Buenos Aires ©Getty Images

International Olympic Committee (IOC) vice-president John Coates, chairman of the IOC's Tokyo 2020 Coordination Commission, stated at the time that venue changes would only be allowed with the full support of sport governing bodies.

Coates has since said that the need to make maximum use of existing facilities overrode Tokyo's eight kilometre philosophy under which plans had been laid to build 10 new venues within eight kilometres of the Olympic Village - this at a time when compactness was one of the cardinal Olympic virtues.

Confirming the Movement's changed priorities, IOC President Thomas Bach promised on Saturday (December 6) that an immediate review into possible changes for both Tokyo and the Pyeongchang 2018 Winter Games would be undertaken if proposed Agenda 2020 recommendations were approved, as they were on Monday.

According to the Tokyo 2020 candidature file, the total spending for the 37 competition venues for Tokyo 2020 was provisionally forecast at JPY¥455.4 billion (£2.7 billion/$4.5 billion//€3.3 billion).

Tokyo says it remains unclear how many sports will be affected by the review and how much money can be saved.

"Tokyo 2020 has been reviewing the original venue plan since June this year to further enhance the quality and ensure the success of the Games," a Tokyo 2020 spokesman told insidethegames.

"The review has been being conducted from the perspectives of legacy, the impact of the Games on Tokyo residents and venue construction and maintenance costs.

"The Olympic Agenda 2020, unanimously adopted by the Session just yesterday, is promoting maximum use of existing sporting facilities for a reason of sustainability.

"We believe that the broad direction of our reviewing work is in line with the philosophy of the Agenda.

"We will remain at the best effort to achieve the truly sustainable Games by continuously working closely with IFs and the IOC."