The costs of building a new National Stadium under a now-scrapped design were estimated to be ¥346.2 billion in 2013, far above the ¥300 billion the government has admitted to so far, according to documents submitted Wednesday to a government meeting.

The figure is also sharply higher than the ¥130 billion the government said it had estimated when it held a tender for the stadium design in 2012. The facility was to be the centerpiece for the 2020 Tokyo Olympics.

The figures are from documents the Japan Sport Council, the stadium operator, gave to a meeting of the sports ministry’s third-party committee reviewing the sequence of events widely considered a fiasco.

The JSC received the estimate of ¥346.2 billion from a design firm’s joint venture in July 2013, shortly before Tokyo was chosen as the host nation. This prompted the sports ministry to instruct the JSC to reduce the costs.

The estimate covered the costs of realizing a gross floor space of 290,000 sq. meters, the costs of the architectural design, and for meeting the requests of various sporting associations. The design was the work of Iraqi-British architect Zaha Hadid’s firm.

Although the sports ministry ordered a reduction in costs, it was not until October 2013 that sports minister Hakubun Shimomura told the Diet that the total construction cost would reach ¥300 billion.

The JSC, reviewing the facility’s floor space and height, trimmed the costs to ¥162.5 billion by the time the stadium’s basic design was agreed.

However, in January this year, the general contractor scheduled to take over construction presented an estimate that the costs would total ¥308.8 billion even under the adjusted design, due in part to soaring materials costs.

The estimated cost came down to ¥252 billion in the final plan approved in July, but this was still nearly double the initial estimate of ¥130 billion. The government decided last month to scrap the plan in response to mounting public criticism.

The head of the third-party committee, Noboru Kashiwagi, a University of Tokyo emeritus professor, told reporters the panel has so far held hearings with about a dozen government and JSC officials involved in the project.

The committee is expected to compile a report in mid-September on why the estimates changed repeatedly and how the stadium’s design was selected, to determine who was responsible.