Tokyo Gov. Yoichi Masuzoe told a city assembly meeting that the overall plan for the venues needs to be revised.
"We must respond to concerns over rising facilities costs, including rising costs for labour and construction materials," Masuzoe said. "We will review the plan as soon as possible from that point of view and revise what needs to be revised appropriately and promptly so that there will be no obstacles for the preparations for the games."
Japan has already informed the International Olympic Committee about its intention to review and revise its plans, the broadcaster NHK cited Masuzoe as saying.
The IOC, under new President Thomas Bach, is currently looking at ways of reducing the costs of hosting future Olympics. Several cities declined to bid or have dropped out of the race for the 2022 Winter Games because of financial concerns.
Yoshiro Mori, a former prime minister who heads Tokyo's Olympic organizing committee, issued a statement saying that Masuzoe and other members of the panel agree on the need to make changes.
The statement did not refer specifically to plans to replace Tokyo's National Stadium with a colossal, 80,000-seat facility, the centerpiece of the city's Olympic bid. The proposed new stadium has caused protests over its size, cost and design.
The Japan Sports Council has already scaled back its original proposal to spend 300 billion yen ($3 billion) on a 75-meter-tall stadium to a still-hefty169 billion yen ($1.7 billion). It recently presented its plans for the stadium to the Olympic organizers, saying it did not envision revising the basic design concept but would take other concerns into consideration.
Mori said he would convene a meeting of the Olympic Board on Thursday to discuss the way forward.
He said one of his priorities is "to seek ways to further enhance the quality of the games, and ensure that we provide a sports-oriented legacy that will enrichen the health and lifestyles of the people of Tokyo and the whole of Japan."
Tokyo, which hosted the 1964 Olympics, won the right to host the 2020 Games last September with a plan emphasizing the city's safety and advanced infrastructure. Of the 33 competition venues, 28 will be within 5 miles (8 kilometres) of the Olympic Village, which will be built on reclaimed land in Tokyo Bay.