In a series of tweets, SoftBank Group Corp.'s founder and CEO Masayoshi Son expressed bewilderment and concern about the Tokyo Olympics going ahead amid Japan's slow-going vaccination drive during the COVID-19 pandemic.

"Currently more than 80% of people want the Olympics to be postponed or canceled. On whose and on what authority is it being forced through?" the billionaire executive wrote in a Twitter post in Japanese.

In a follow-up tweet late on Sunday, he wrote: "Does the IOC (International Olympic Committee) have the power to decide that the games will go ahead?

"There's talk about a huge penalty (if the games are cancelled) but if 100,000 people from 200 countries descend on vaccine-laggard Japan and the mutant variant spreads, I think we could lose a lot more: lives, the burden of subsidies if a state of emergency is called, a fall in gross domestic product, and the public's patience."

Son's tweets followed comments on Friday from International Olympic Committee (IOC) Vice President John Coates that the Olympics would "absolutely" go ahead even if Tokyo was under a state of emergency.

With just two months to go until the Summer Games, much of Japan remains under state-of-emergency restrictions, including Tokyo, as the spread of infectious coronavirus variants strains the medical system.

That has kept the majority of the public opposed to holding the games this year. A Reuters corporate survey found nearly 70% of Japanese firms also want the Olympics either canceled or postponed.

Japan has vaccinated just 4.4% of its population, the slowest among the world's larger, rich countries. Japan has recorded 711,360 coronavirus infections and 12,232 COVID-19 deaths so far.