The saga of the Tokyo 2020 Olympic Stadium has moved to another stage, with the Japanese Sports Council revealing two potential designs. The winner is expected to be announced this month.

Both designs have construction budgets of ¥153bn (US$1.26bn, €1.14bn, £832m), putting them within the council's limit of ¥155bn (US$1.28bn, €1.16bn, £848m).

Design A has a flat roof and shrubbery along its outer concourse, stands 50m tall (164ft) and is a combined steel and wood structure.

Design B, standing at 54.3m (178ft), features outer glass walls and 72 wooden pillars.

The Japan Sports Council did not identify the architects behind the designs, but reports in Japan indicate that one proposal may have been submitted by a joint venture involving construction company Taisei Corp, while the other may be by a venture between Takenaka Corp, Shimizu Corp and Obayashi Corp.

Work on both would have a completion date of 30 November 2019 for all elements apart from landscaping and surrounding work.

“We will work to ensure a stadium that will be loved by all,” said Sports Council president, Kazumi Daito.

Zaha Hadid Architects (ZHA) was originally selected to design the Olympic stadium for 2020, but Japanese president Shinzo Abe withdrew the plans, saying stadium costs had increased beyond budget.

Hadid blamed Japanese procurement methods for the price increases.

ZHA considered re-tendering in conjunction with partners Nikken Sekkei, but could not secure a construction partner, so pulled out of the running in September.

Earlier this month the Japanese Sports Council struck a funding agreement for the stadium with Tokyo authorities and the Japanese government.

BACKGROUND BRIEFING

Zaha Hadid Architects originally won the contract to design the stadium in November 2012, ahead of other bidders such as Populous, UNStudio and Toyo Ito. They beat Cox Architecture into second place and SANAA into third.

But the bid was always controversial, and this summer, in series of astonishing events, ZHA was given formal approval on 7 July, only for the scheme to be cancelled by Japanese prime minister, Shinzo Abe, just 10 days later.

In announcing the cancellation, he said the cost of the $2bn stadium “has just ballooned too much”. The design had also suffered stinging criticism from a number of leading Japanese architects.

A succession of skirmishes followed, with ZHA issuing a robust defence of their design, blaming the huge cost increases on Japan's overheated construction market and the tendering process for the building, in which contractors were appointed before they submitted cost estimates: "Our warning was not heeded that selecting contractors too early in a heated construction market and without sufficient competition would lead to an overly high estimate of the cost of construction,” they said.

Sir Richard Rogers, who was on the jury that first selected the design, came out publicly in support of ZHA, saying: "I'd like to express my concern about the decision to cancel Zaha Hadid Architects' design at this late stage.

"For Japan to lose their nerve now, and abandon a design by one of the world's foremost living architects that was selected by an international jury, will not only result in a poorer quality stadium for the Tokyo 2020 Olympics, but also in damage to Japan's international credibility, and reputation as a promoter of world-class architectural design."

ZHA were not going to go quietly, so when Japan announced a new design and build competition for the job on 1 September, they announced they would re-bid, working with Nikken Sekkei. “We believe the best way to respond to the new brief is to maximise the use of the expertise and experience gained by the design team over the past two years,” the firm stated.

The revised guidelines for the new competition capped the cost at ¥155 billion (£850 million) – a significant reduction compared to the ¥250 billion (£1.37 billion) estimate for ZHA's initial design. The amount of seating has also been reduced.

The new competition requires bidders to demonstrate capabilities in planning and design, construction and construction supervision, and to form consortiums of firms to cover all these capabilities and in last night's statement, Nikken Sekkei and ZHA said they had not been able to secure a construction company in their consortium and that "as a result they are unable to enter the competition.”

ZHA said: "It is disappointing that the two years of work and investment in the existing design for a new National Stadium for Japan cannot be further developed to meet the new brief through the new design competition.

"Nikken Sekkei and ZHA are prepared and able to deliver a cost-effective stadium that meets the revised brief, is ready in good time for the 2020 Games and provides a new home for sport in Japan for generations to come," they said.

There is one last opportunity for ZHA to maintain an involvement with the project – the practice says it hopes to lend the knowledge it has gained during the project to whoever eventually wins the competition: "While the current competition is closed to the existing design team, we stand ready to use the wealth of detailed knowledge and expertise, built up through the thousands of hours dedicated to the project, to assist the National and Tokyo Governments and Japanese people deliver a stadium fit to welcome the world in 2020 and go on to host national, international and community events for the next 50-100 years," said the statement.

Tokyo’s 2020 Olympic cycling venues approved by IOC

Tokyo City Government to fund a quarter of the 2020 Olympic stadium

Zaha Hadid pulls out of Tokyo stadium competition citing inability to secure construction partner