Tokyo 2020 Games chief Yoshiro Mori has formally apologized to the International Olympic Committee (IOC) after plans for the city's new Olympic stadium were scrapped earlier this month over ballooning costs.
Mori, who presented a progress report to the IOC Executive Board on Wednesday, said the Olympic body had accepted Japan's review of stadium plans and offered its support as organizers now face a race against time to get it ready for the Games.
"I extended my sincere apologies that we had to change the plan," Mori told reporters. "(IOC) President Thomas Bach gave us his support and confidence.
"Any plan has to have room for improvement and it is natural to improve the plan and the IOC will give its full support for the improvement."
Costs for the New National Stadium, set to be the centerpiece of the Games, soared to $2.1 billion, nearly twice original estimates, sparking widespread outrage that prompted Prime Minister Shinzo Abe to abandon the initial design.
The decision also meant that key matches at the 2019 rugby World Cup are without a home, damaging Japan's reputation for organizational prowess, especially in the sporting world.
"(President) Bach has expectations that we can improve the plan. He gave us encouragement to work hard to complete the stadium by Games time. He said this cannot be left to the Japanese government alone," former prime minister Mori added.
The IOC said it would now be part of the new stadium tender to help monitor its progress.
"We have made it very clear here that we want to be involved in the tender," Bach said.
"So the tender is worded in a way that all Olympic requirements are taken into consideration and that there are no surprises in half a year or a year."
While Japan wants a cheaper stadium, construction material costs have risen since the city's bid won the IOC vote in 2013, Tokyo 2020 CEO Toshiro Muto said.
"There is a surge in prices for various construction material. There is higher cost and we will focus on cost reduction," Muto said.
"There will be an inflation (of prices) but we will make sure we minimize that.
"For us, the priority is to have it completed before the Olympics. We are sure and confident the stadium will be completed on time."
On Tuesday, the firm of architects whose design was scrapped said the billowing costs were due partly to an uncompetitive selection of contractors and that warnings over this were ignored by Japan.