Image copyright EPA Image caption Hakubun Shimomura said he wanted to take responsibility for the problems

Japan's Education and Sports Minister Hakubun Shimomura has tendered his resignation over cancelled plans for the 2020 Tokyo Olympic Stadium.

British-Iraqi architect Zaha Hadid's original design was ditched in July as estimated building costs almost doubled, reaching $2bn (£1.3bn).

Mr Shimomura said he had been asked to stay on until a planned cabinet reshuffle, but would repay some salary.

A new stadium design is due to be chosen by November.

Image copyright AP/Japan Sport Council Image caption Tokyo fought off competition from Madrid and Istanbul to win the right to host the 2020 Olympic Games

Concerns have already been raised about whether that design will be completed in time for 2020 - the first time the city has hosted the Summer Games since 1964.

As well as objections to its ballooning cost, Ms Hadid's design was criticised by some in Tokyo for its similarly huge size and its unusual shape.

Image copyright AP/Japan Sport Council Image caption Ms Hadid's design was likened by some to a space ship or a giant bicycle helmet

A close ally of conservative Prime Minister Shinzo Abe, Mr Shimomura runs the Ministry of Education, Culture, Sports, Science and Technology, which is in charge of overseeing the Olympic Games.

Speaking at a press conference at his ministry following a meeting with the prime minister, Mr Shimomura said he told Mr Abe he wanted to take responsibility for the stadium problems.

"It is true that this has caused much concern and inconvenience," he said.

He added that he had first heard of the inflating costs and delays in April, "which is why I have decided to return the six months' worth of pay I have received from that day onwards".

His offer to quit came after an independent investigation into the fiasco.

Local reports said the panel pinned responsibility on the government body overseeing the project, the Japan Sports Council, and Mr Shimomura's ministry. Former Prime Minister Yoshiro Mori, president of Tokyo's organising committee, was also blamed.

Image copyright Tokyo 2020/ Theatre de Liege Image caption The designer of the Olympic logo (left) denied copying a Belgian artist's work (right)

Plans to host the 2019 Rugby World Cup have also been thrown into doubt by the cancellation of Ms Hadid's original plans, as organisers now have to find an alternative final venue.

Olympic organisers are also looking for a new logo, after a Belgian artist complained that a logo he designed for a theatre, had been copied.

Those allegations have been denied by both Olympic organisers and the Japanese logo designer himself but he admitted his team did copy other work in the past, and the Tokyo Games committee said too many doubts had been raised for it to be used.