NHK has learned that the Fukushima prefectural government's estimate of the current number of evacuees from the 2011 disaster is about 24,000 less than the figure calculated by local municipalities.
Earlier this month, officials said about 80,000 people were still living in shelters because of the tsunami and nuclear accident.
This includes 17,781 residents of 5 municipalities around the crippled Fukushima Daiichi plant who were evacuated to other parts of the prefecture.
But NHK's survey found 42,030 people had left these municipalities -- about 24,249 more than the prefectural government's figure.
Officials from the 5 municipalities say their estimate includes all the people who evacuated to other parts of the prefecture, but the Fukushima government's calculation excludes those who moved into public housing or acquired new homes in other areas of the prefecture.
A visiting associate professor at Fukushima University, Kazuhiko Amano, says many residents still dream of returning to their hometowns even after they have found a place to live.
He says surveys should also cover the type of housing and whether evacuees are living normal lives. He says the prefectural government's counting method may underestimate the number of people who actually need support.