A 102-year-old man has killed himself in a newly declared no-go zone around Japan's crippled nuclear plant because he was depressed at having to leave his home, a report said on Thursday.

The centenarian, the oldest resident of Iitate village, 40 kilometers from the Fukushima Daiichi plant, took his own life after talking to his family about evacuating, Jiji Press reported.

"Before the suicide, the oldest resident of the community discussed evacuation plans with his family, municipal officials said, adding that they suspect the man was depressed at the idea that he would have to leave his place," Jiji reported.

Iitate was one of a number of areas the central government declared off-limits earlier this week because of concerns over the effect of long-term exposure to radiation from the leaking nuclear plant.

Thousands had been evacuated from a 20-km exclusion zone around the plant, which began spewing toxic radiation after its cooling systems were disabled by the March 11 tsunami that hit Japan.

Japan's respected emperor visited the country's earthquake and tsunami-ravaged disaster zone for the first time on Thursday. In Asahi, where 13 people were killed and around 3,000 homes damaged, Emperor Akihito and Empress Michiko got their first look at the devastation, somberly gazing at a plot of land where a home once stood and commiserating with evacuees at two shelters.

The royal couple kneeled on mats to speak with the survivors, who bowed in gratitude and wiped away tears. One evacuee, who has trouble speaking, wrote "I will keep striving" in a small notebook that he showed to the emperor and empress.