San Francisco, Jul 24 (IANS): The Chinese cryptocurrency whizkid who paid $4.6 million to enjoy lunch with billionaire industrialist Warren Buffett has postponed their meeting in San Francisco blaming kidney stones.

Justin Sun, the 28-year old founder of Tron -- the 11th largest cryptocurrency with a $1.5 billion market capitalisation -- won the lunch with Buffett in a charity auction, Markets Insider reported on Tuesday.

However, Sun's rescheduling has fueled reports that the Chinese government has barred him from leaving the country.

Chinese news outlet The 21st Century Business Herald published a story accusing Sun of unlawful fundraising, operating illegal gambling services and illegal involvement in the pornography business.

Denying the reports, Sun launched a live video chat of himself in San Francisco with the Bay Bridge in the background.

"I'm not feeling quite well but I think we gonna postpone but definitely looking forward to it," Sun was quoted as saying in the live stream. "It's pretty comfortable in San Francisco."