Demolition of the old National Stadium was supposed to begin on Sept. 29 but has been delayed by bidding problems. A new round of bidding has been ordered, further delaying the start of demolition until the middle of December.
Olympic organizing chief Yoshiro Mori, who also serves as president of the Japan Rugby Football Union, told a meeting of city officials in charge of the Rugby World Cup he was worried about the delays.
Olympic organizers plan to replace the old stadium with a new 80,000-seat venue that will also host the Rugby World Cup.
"I'm worried," Mori said regarding the delays. "The Olympics are for Tokyo, but we will have about 12 Rugby World Cup venues spread around the country. Because we'll open up all of Japan for everyone to see, we want the success of 2019 to carry over to the Tokyo Olympics."
Plans for the stadium, designed by award-winning British-Iraqi architect Zaha Hadid, have been plagued by problems, including complaints from some prominent architects, who say the design is too big and expensive.
The futuristic design to replace the National Stadium was initially projected to cost 130 billion yen ($1.3 billion), but the estimate quickly ballooned to more than double that, although it is expected to be scaled down.