The architects behind Tokyo's new National Stadium have rejected reports that they may be fired from the project as criticism mounts over the building's cost and appearance.

A weekend report in the Hochi Shimbun said Olympic chiefs were considering canceling the contract with Zaha Hadid Architects, which was chosen to design the showpiece stadium in a restricted-entry competition in 2012, unless the design could be modified to meet budget and time restrictions.

The site is currently being cleared in preparation for construction.