A Tokyo Metropolitan Government Task Force suggested changes to three venues in September in a bid to cut a budget which was otherwise expected to balloon to ¥3 trillion (£22 billion/$30 billion/€26 billion).

Proposed changes for swimming and volleyball venues were put forward as well as, crucially, a suggested shift in the rowing and canoe sprint course 400 kilometres away from Tokyo to the Naganuma rowing course in Tome, Miyagi Prefecture.

Technical representatives from both the Metropolitan and National Governments met with Tokyo 2020 and International Olympic Committee (IOC) delegations for extensive talks today.

No decisions have been announced, however, with their feedback now expected to be given to the heads of the four bodies here on Tuesday (November 29).

These are Tokyo Governor Yuriko Koike, Olympics Minister Tamayo Marukawa, Tokyo 2020 President Yoshirō Mori and IOC vice-president and Tokyo 2020 Coordination Commission chair, John Coates.

None of these figures were present today.

At least part of the meeting on Tuesday is expected to be open to the media, with it hoped that final decisions will be made there.

"We discussed areas where the IOC can make a contribution," IOC executive director for the Olympic Games Christophe Dubi said after today's session.

"This includes overlay and temporary construction costs as well as transportation and technology and energy issues.

"An immense amount of good collaboration has been achieved since our last meeting three weeks ago."

Dubi was repeatedly asked to elaborate on what venues they would recommend.

"Our duty was to study each and every option," he said.

"The political leaders will then make a final decision."

He also refused to confirm that final decisions will definitely be made on Tuesday.

He did reveal that three options are on the table for the rowing and canoe sprint venues: one being Naganuma and the other two both consisting of different plans to develop the Sea Forest venue in Tokyo Bay. 

One or both of these proposals is expected to be a down-scaled version of the initial plans revealed during Tokyo's bidding phase.

It appears likely that one of these two will be chosen rather than the course 400km away.

The discussions come alongside a three day Rio 2016 debrief here in which Brazilian officials including Organising Committee head Carlos Nuzman will provide feedback on different aspects of Olympic and Paralympic operations.

A Coordination Commission inspection will then take place on Thursday and Friday (December 1 and 2) before an IOC Executive Board meeting in Lausanne from December 6 to 8 at which another Tokyo 2020 presentation will be made.