TOKYO — Japan moved closer to restarting the first of the nation’s idled nuclear plants as the prime minister signaled that he might order a start-up as early as next week and as a new round of scrambling to persuade local leaders to drop their opposition appeared to be working.

A decision to allow the plant to begin operating would end a standoff of months between Prime Minister Yoshihiko Noda, who has worried that the lack of nuclear power would create a further drag on the economy, and local leaders made skittish by last year’s nuclear disaster.

On Thursday, the most vocal and influential critic of Mr. Noda, Mayor Toru Hashimoto of Osaka, said he had dropped his opposition, at least for the time being, because of Japan’s energy needs. He also said the government had addressed his concerns by promising to post a top official at the plant, in Ohi, to directly oversee safety, and move forward with the creation of a more independent nuclear regulatory agency.

The Ohi plant supplies electricity to the heavily urbanized Kansai region of western Japan. The two reactors there would be the first of Japan’s 50 functional commercial reactors to go back online after the accident at the Fukushima Daiichi plant.