The government is considering modifying the construction plan for the new National Stadium, exploring ways to curb the unexpectedly high construction costs of ¥252 billion, Chief Cabinet Secretary Yoshihide Suga said Thursday.

Asked if the government may change the basic design for the 2020 Tokyo Olympics’ main venue, featuring two gigantic keel arches for a roof, Suga remained noncommittal.

“Nothing has been decided over such matters as of now,” Suga told a regularly scheduled news conference.

“At any rate, we need to carry out various efforts to minimize the financial burdens on the nation,” he said.

Having a private-sector business manage the stadium’s operations after the Olympics may be among possible cost-cutting measures, Suga said. But he didn’t elaborate further.

The estimated cost to build the stadium has surged from the original ¥130 billion to ¥252 billion without public explanation of cost breakdowns, drawing outrage from many voters.

Top government officials believe that festering public anger has helped lower the Cabinet’s approval ratings in various media polls and could seriously damage Prime Minister Shinzo Abe’s administration.

“It’s really a headache. It’s affecting the approval rates,” said a high-ranking official close to Abe, speaking on condition that he would not be named.

Speculation is rife that the government will withdraw the current design by Iraqi-British architect Zaha Hadid, which was adopted through an international competition in 2012, and instead construct a low-cost stadium based on a different design.

But this would force the government to again carry out an international design competition, which would involve a long public notification period in advance.

The official warned that this might mean that the new stadium wouldn’t be finished before the 2020 Olympics, let alone the 2019 Rugby World Cup to be hosted by Japan, for which the venue is also to be used.

“We haven’t checked if (the plan) is workable after Tokyo was chosen (in 2013 to host the Olympics in 2020). That’s our mistake,” the official said.

To change the basic design, the government would need to persuade former Prime Minister Yoshiro Mori, now serving as president of the Tokyo Organizing Committee of the Olympic and Paralympic Games.

Mori, who served as president of the Japan Rugby Football Union until June, reportedly promised the World Rugby Organization that Japan would build an entirely new stadium to host the 2019 Rugby World Cup.

Mori is thus believed to be reluctant about any major design changes that would make using the National Stadium for the Rugby World Cup impossible.

Kyodo News has reported that the government is considering either changing the basic design of the stadium or extending the construction period to lower the cost. In either case, the stadium would not be finished before the Rugby World Cup, Kyodo reported.

In a separate move Thursday, architect Tadao Ando, chairman of the design competition committee that chose the current stadium design, held a news conference in Tokyo to speak about the controversy.

Ando said he has no idea why the estimated costs soared from the original budget of ¥130 billion.

“I, too, want to ask” why the cost rose so dramatically, said Ando, 73, a winner of the prestigious Pritzker Architecture Award.

Many officials involved in the stadium project have criticized Ando for not explaining the reasons for the unexpected rise.

He made no public appearances after July 7, when the Japan Sport Council, a special organization affiliated with the education and sports ministry, confirmed the price tag for the new National Stadium had climbed to ¥252 billion.

But according to Ando, his competition committee was tasked only to choose a blueprint for the stadium, and committee members did not discuss details of cost breakdowns.

Ando also maintained that he did not show up at the July 7 meeting and an ensuing news conference because of his tight schedule and poor health condition following surgery last year for pancreatic cancer. “I don’t get why I became the only one to be blamed for everything just for being absent from the meeting,” Ando said.

According to the JSC, a group of experts tasked by the council estimated that construction costs of Hadid’s design would not exceed ¥130 billion, and the JSC reported it to Ando’s committee during the competition processes.

Ando said he was overwhelmed with Hadid’s ambitious design, but just “thought Japan could go through this complicated construction” with the budget framework of ¥130 billion.

But he also confessed he had never been involved in such a big project, which involves building a structure large enough to hold 80,000 people.