Tokyo Olympics organisers unveiled a smaller budget of up to $17 billion after coming under pressure to cut ballooning costs.

The figure, down from November's pledge to cap expenditure at $17.78 billion, follows warnings that the bill for the 2020 Games could soar as high as $30 billion.

Organising committee chief executive Toshiro Muto on Wednesday said the entire Games budget will be between ¥1.6 trillion and ¥1.8 trillion, which he put at $15-16.8 billion.

Under the latest exchange rate, the same yen figure is worth $13.6-15.3 billion. The 2016 Rio Games cost $12 billion, while London 2012 came $13.7 billion under the exchange rate of the time.

Wednesday’s figure, the most complete budget yet for Tokyo 2020, comes after officials scrambled to slash the costs of building some Olympic venues.

It was revealed at talks between the Games' organisers, the International Olympic Committee (IOC) and the Tokyo and national governments, who are meeting regularly to try to cut costs.

"This does give the overall picture," IOC vice-president John Coates said by videolink from Sydney.

"We are pleased with the progress you are continuing to make," he said, adding: "We think that we can work with you to find… more savings."

Tokyo governor Yuriko Koike, who was elected in 2016 vowing to bring down costs, said ¥40 billion would be saved after a review of the canoeing, volleyball and swimming venues.

Koike said the organising committee and Tokyo and central governments will discuss further specifics early 2017, including "cost-sharing".

In the battle to cut costs, she had proposed moving the canoeing 400 kilometres north of Tokyo to Miyagi prefecture, one of the areas hardest hit by Japan's 2011 tsunami disaster.

But the idea faced resistance from the organising committee, which argued that changing sites was impractical and could end up costing more.

Koike gave up the plan in November and announced that canoeing will stay in Tokyo as planned, but with the venue built at a sharply reduced cost.

In the previous four-way meeting in November, Muto said the organising committee's working budget was capped at less than ¥ two trillion ($ 17.78 billion) and officials are committed to pushing it lower.

But Coates refused to accept the figure and said overall costs would have to come down significantly.