Japan's Tokyo Electric Power has conceded the Fukushima disaster played a part in a farmer's suicide, lawyers said Thursday, its first admission of culpability in such a case.

The utility, known as TEPCO, has reached an out-of-court settlement with the bereaved family of Hisashi Tarukawa, a Fukushima farmer who took his own life days after the Fukushima Daiichi nuclear power plant went into meltdown.

It was the first time the company has accepted in a settlement that the nuclear disaster at its plant was a factor in a suicide, the lawyers said, adding that terms of the settlement package were not being made public.

The 64-year-old hanged himself from a tree in a vegetable field after authorities banned shipments of some farm produce from Fukushima because of fears it was contaminated by radiation.

"I just didn't want TEPCO to keep saying no one was killed because of the nuclear accident," said Kazuya Tarukawa, the dead man's 37-year-old son.

He said he still wanted the company to make an official apology for his father's suicide.

"Does TEPCO think everything is finished if money is paid?" he said.

"I want them to come to my house under the name of the company and bow to my father's altar. My fight is not over yet."

Lawyer Izutaro Managi said companies facing lawsuits are often reluctant to give official apologies for fear of their being interpreted as an admission of full responsibility.

TEPCO refused to comment on the details of the settlement.

Fukushima was the site of the worst nuclear crisis in a generation. Reactors went into meltdown, spewing radiation over a wide area, after a 9.0-magnitude quake triggered a massive tsunami on March 11, 2011.

Although the natural disaster that spawned the emergency claimed more than 18,000 lives, no one is officially recorded as having died as a direct result of the atomic catastrophe.

However, tens of thousands of people were forced to leave their homes and businesses in the area around the site and many remain evacuated, with scientists warning some places may have to be abandoned forever.

The cash-strapped operator of the crippled plant, which remains in a precarious state, faces growing compensation claims from Fukushima victims, including the bereaved families of suicide victims like Tarukawa.

Last month the 35-year-old widow of a cattle farmer filed a lawsuit against TEPCO to demand 126 million yen ($1.27 million) in damages after her husband killed himself when he was ordered to stop shipments of milk following the disaster.

The government has officially recognised that at least 80 people had committed suicide by December last year because of the Fukushima disaster.

Japan has one of the highest suicide rates in the world, according to the OECD, with around 30,000 people taking their lives each year.

Doctors have warned that the earthquake-tsunami and the nuclear crisis it caused were leading to higher than usual incidences of mental health problems, adding that an upswing in suicides in the area was a likely consequence.