The architect developing Japan’s National Stadium for the Tokyo 2020 Olympic Games has publicly refuted claims his studio have copied from an earlier design submitted by Zaha Hadid Architects (ZHA).

According to the Japan Times newspaper, Kengo Kuma spoke at a news conference on 15 January in Tokyo to deny that significant similarities exist between the two designs for the stadium.

“I believe if you take a look at Zaha Hadid’s design and mine, you can see very different impressions of the building,” he is reported to have said.

ZHA – who are embroiled in a row with the Japan Sports Council (JSC) over its decision to drop them from the stadium project – have said that “remarkable similarities” exist between the stadium layout and seating bowl they proposed, and the one created by Kuma.

Yesterday (14 January) ZHA submitted a report to the JSC outlining these claims in detail. In a statement, the firm said the document “will form the basis for the discussions we hope to resume shortly with the JSC to resolve the important issue of the use of valuable design work that is currently the copyright of ZHA and the original design team.”

The studio also said it has received and rejected a written request from the JSC to hand over copyright for the design and sign a non-disclosure agreement in order to receive an overdue payment for its work on the project.

At the press conference, Kuma reportedly said similarities in design are inevitable when trying to create a seating configuration that can give 80,000 spectators a clear view. He added that his stadium is lower and flatter than ZHA’s design and uses different natural materials in a bit to minimise construction costs and integrate the stadium with its surroundings in the leafy Jingu Gaien area.

He also denied suggestions that ZHA were dropped from the project because they are a foreign studio. According to the Japan Times he added that “it is perhaps difficult for architects from other countries to work in Japan” due to the language barrier and the way in which meetings are conducted.

While the ¥149bn (£806m, US$1.2bn, €1.1bn) National Stadium is on course to be completed by November 2019, the row over its development threatens to overshadow the project.