Japan plans to scale back the main stadium for the 2020 Tokyo Olympics as the government runs short of money and time, the country's sports minister said Monday

Hakubun Shimomura said a planned retractable roof wouldn't be built in time for the games, and some of the 80,000 seats would be temporary ones, according to Japanese media reports.

Shimomura, whose ministry oversees sports, education and science, made the remarks in an exchange of views with Tokyo Gov. Yoichi Masuzoe.

He asked if the city of Tokyo could shoulder 50 billion yen ($418 million) of the 169 billion yen construction cost. Masuzoe was non-committal, Kyodo news service said.

Plans for the new stadium have been criticized by some prominent architects, who say the design is too big and expensive. It is due to be completed in time to host the Rugby World Cup in Japan in 2019.