Japanese social media reacted with a storm of outrage to a video by YouTube star Logan Paul showing a suicide victim in a forest near Mount Fuji, as anger spread over the now-deleted video on Wednesday.

Angry comments flooded Twitter after Paul, who gained notoriety on social media and has a popular video blog or "vlog", apologised for the footage, which was reportedly viewed six million times.

The video shows the 23-year-old discovering a body in Aokigahara, a dense woodland at the foot of Mount Fuji known as "the Japanese Suicide Forest", in a country that has long struggled with some of the highest suicide rates in the developed world.

As news of the video and apology was reported in Japan Wednesday, social media erupted with indignation over the film, which showed a man who had hanged himself.

"It is insane to show to the world the body of someone who died after being depressed. Shame on you," said one Twitter user @j_rivoluzione.

Others objected to Paul's appearance in a novelty hat, while outtakes showing the US internet celebrity laughing and joking about the incident also stirred anger.

"It's good to raise awareness but you can do it without filming a person who committed suicide," @spiffymiffy1 said.

"It looks like he did it for self-satisfaction. Suicide and depression are serious issues. There's nothing funny about them."

Others said Paul's actions were irresponsible, with teenagers and tweens making up his subscriber base of 15 million.

In his apology, Paul said he had posted the video in a mistaken effort to draw attention to the problem of depression and suicide.

"It's easy to get caught up in the moment without fully weighing the possible ramifications," he said in his statement.

"I thought I could make a positive ripple on the internet, not cause a monsoon of negativity", he said, in comments that sparked derision and anger.

Actress Anna Akana was among many in the US and elsewhere to hit out at Paul.

"When my brother found my sister's body, he screamed with horror & confusion & grief & tried to save her," she tweeted.

"You do not walk into a suicide forest with a camera and claim mental health awareness."

Japan has the highest suicide rate of any Group of Seven industrialised nation, with more than 20,000 people taking their own lives each year.

Aokigahara, located 100 kilometres (63 miles) west of Tokyo, has become so notorious as a spot for desperate people to kill themselves that authorities have put up signs among the trees urging people with self-destructive thoughts to contact a suicide prevention group.

"Life is a precious thing... Think again about your parents, siblings and children," the signs say.

Local officials have also organised daily patrols to prevent suicides from taking place.

The suicide rate in Yamanashi prefecture, where the forest is located, was the worst in Japan for eight years until 2014.

Suicides in Japan have fallen since their peak of 34,427 in 2003, with 21,897 taking their own lives in 2016.

Google-owned YouTube indicated the video was removed because it violated the video-sharing platform's terms of service.

"Our hearts go out to the family of the person featured in the video," a Google statement said.

The statement added that YouTube prohibits "violent or gory content posted in a shocking, sensational or disrespectful manner" and that such content is allowed only "when supported by appropriate educational or documentary information."