Mr Ma was the most high-profile Chinese billionaire to have disappeared amid a crackdown on tech entrepreneurs.

He recently returned to China after more than a year overseas, according to the South China Morning Post.

The Alibaba-owned newspaper said he had made a short stopover in Hong Kong, where he met friends and also briefly visited Art Basel, an international art fair.

It added that Mr Ma has been travelling to different countries to learn about agricultural technology, but made no reference as to why he had disappeared from public view in recent years.

Mr Ma, a former English teacher, met staff and toured classrooms at the Yungu School in Hangzhou, the city in which Alibaba is headquartered.

He talked about the potential challenges of artificial intelligence to education, according to the school's social media page.

"ChatGPT and similar technologies are just the beginning of the AI era. We should use artificial intelligence to solve problems instead of being controlled by it," he said.

Once the richest man in China, Mr Ma gave up control of financial technology giant Ant Group in January this year.

It was seen by some commentators as further evidence that he had fallen foul of the Chinese Communist Party for becoming outspoken and too powerful.

In October 2020, Mr Ma told a financial conference that traditional banks had a "pawn-shop mentality".

The following month, Ant's planned £26bn stock market flotation, which would have been the world's largest, was cancelled at the last minute by Chinese authorities, who cited "major issues" over regulating the firm.

Since then, there have been reported sightings of him in various countries including Spain, the Netherlands, Thailand and Australia.

Last November, the Financial Times newspaper reported that Mr Ma had been living in Tokyo, Japan for six months.

When Mr Ma first stopped making public appearances, it was rumoured that he had been placed under house arrest or had been otherwise detained.