Christmas for one homeless pastor and his itinerant flock, forced to flee when Japan's nuclear crisis erupted, will have echoes of its origins this year as they gather in a shelter far from home.

The reverend Akira Sato says he and his 50-strong congregation are expecting an "unforgettable" Christmas a long way from the Fukushima Daiichi Seisho (1st Bible) Baptist Church, which lies in the shadow of the crippled power plant.

"This Christmas will be very special. I will never forget it," said the 54-year-old, who is planning to hold his December 25 service at a church in western Tokyo that has offered temporary refuge.

"I often call myself a homeless pastor," Sato told AFP. "We know we won't be able to remain homeless forever, but we do not yet know where we can go. We are still wandering."

Sato has presided over services at the Fukushima church -- whose name, along with the power plant simply means "first" -- since 1982.

The original church was founded in 1947 by an American Baptist missionary. The congregation rebuilt it in 2008 just five kilometres (three miles) from the atomic plant.

Then on March 11 a 9.0 magnitude undersea earthquake spawned a towering tsunami that crashed into the power station, knocking out its cooling systems and sending reactors into dangerous meltdown.

Along with tens of thousands of other people, Sato and his flock were ordered to leave their church and their homes, which lie inside a declared 20-kilometre no-go zone as radiation levels soared.

Drawing parallels with Moses leading the Israelites out of Egypt, Sato says he took his parishioners from one church to the next, seeking refuge and something to eat, while caring for elderly believers stricken by pneumonia.

"To me, the first week was like a scene from a movie," he said.

As well as the practical difficulties, the group also faced discrimination over rumours that people from Fukushima had been exposed to radiation and could "infect" others.

"We were told we were dirty simply because we were from Fukushima," Sato said. "We were so frustrated. We were so sad. The disaster destroyed everything."

After nine months of wandering -- during which three parishioners died -- the group has ended up at a church and an adjacent cottage in Tokyo.

Although Christians only account for around only one percent of the country's population, the Japanese capital in December is awash with Christmas cheer.

Buildings and trees are decked with lights and festive music rings through the shops as people buy presents for friends and family.

The liveliness of Tokyo is a welcome relief after the misery of 2011. But, says Sato, it has not all been bad.

"We have lost a lot of things, but we have also gained something we didn't have before," which is a real sense of gratitude, Sato said.

"We were nearly crying with joy when we were first given blankets and warm food," he said.

"Most of all, we are still alive. We had thought we needed a lot of things to live. But that appears to me to have been an illusion now," he added.

"I told myself that this is the reason I became a priest, for this day. As the Bible says: God gives us nothing we cannot bear."

Sato said the nuclear disaster could have been a warning from God about human greed.

"When I temporarily returned to our church in protective gear, the town appeared unchanged.

"Dogs were running and cherry blossoms were in full bloom. Everything was as it used to be. Except for one thing. There were no people. It's like Paradise Lost," he said, referring to the Christian belief that mankind was ordered out of heaven for disobeying God.

"Maybe we sought affluence too much," he said. "Maybe we were too greedy. We could have gone too far. God may be telling us, 'Come back to Fukushima again after you have calmed down.'"

But with the decommissioning of reactors expected to take anything up to 40 years and warnings that tracts of land around the power station will be uninhabitable for decades, Sato has decided he must re-establish his church on higher ground.

He intends to borrow money for a new building in Izumi, southern Fukushima, some 60 kilometres away from their old home.

He plans to name it "Fukushima Daiichi Bible Church, Izumi Chapel," and to build it facing the direction of their old one.

"We need hope and a home," Sato said.

"People cannot live on bread alone. This new church is a symbol of revival. We will sing our hymns every week looking towards our hometown."

The church's multilingual website, where donations can be made to help with building costs is: www.f1church.com