Japan's trouble-plagued new national stadium, the centrepiece of the 2020 Summer Olympics, will cost more than $2 billion to build, nearly twice the original estimate, and be completed two months later than first thought, officials said on Monday.

The new stadium, which will replace a now-destroyed venue built for the 1964 Summer Games, has been beset by woes including sky rocketing costs, feuding over funding and criticism of the design as too grandiose for its intended site.

Education Minister Hakubun Shimomura told a meeting of Tokyo 2020 organisers that Japan will stick with the basic design put forth by United Kingdom-based architect Zaha Hadid and that construction costs will run to 252 billion yen ($2.1 billion).

Construction will begin in October this year and end in May 2019, Shimomura was quoted by Tokyo 2020 CEO Toshiro Muto as telling the meeting.

That will be two months later than originally planned but organisers were quoted by Japanese media as saying it will be done in plenty of time for the Rugby World Cup, set to be hosted by Japan in the autumn of 2019.

"A large change in the design at this point would keep the stadium from being completed in time, and it was also a big sales point for Tokyo's bid," Shimomura was quoted by NHK national television as saying after the meeting.

A retractable roof will not be added until after the Olympics and 15,000 of the stadium's 80,000 seats will be a much simpler movable design than originally proposed, both additional steps to cut costs.

The stadium came in at 130 billion yen in Tokyo bid documents but cost estimates ballooned to 300 billion yen last year, prompting a modest scaling back of the futuristic design, which features two massive arches and has been compared to a spaceship and a bicycle helmet by critics.

Tokyo governor Yoichi Masuzoe has also rebelled at the metropolis being asked to foot some 50 billion yen of the bill, with the two sides making veiled swipes at each other over the issue.

Asked about how much Tokyo might be asked to spend, Shimomura was quoted as saying "the upper limit up to now," implying that requests for 50 billion yen may be renewed, media said.