Eager to get Japan's nuclear-power plants restarted, Prime Minister Shinzo Abe's government is weighing whether to offer a written statement guaranteeing plants' safety.

"We have received requests from local governments to guarantee the safety of specific plants--for example, in a written statement," said Toshimitsu Motegi, the minister who oversees the power industry, at a Tokyo conference Tuesday. "We'll consider what sort of measures we could take to explain" the situation, said Mr. Motegi, who is minister...