“I was informed that he’s getting an additional exam after last week’s exam,” said Suga, who is regarded as one of the main contenders for Abe’s job. “The premier himself said the other day that he wanted to return to work.”

“Abe feels guilty about the idea of taking a break. We need to force him to get rest, even just for a few days,” former economy minister Akira Amari said at the time.

Abe’s return to hospital on Monday coincided with him setting a record for the longest consecutive term in office by a Japanese prime minister.

He was already the country’s longest-serving prime minister, counting his first and second terms in office. But as of Monday, he has been in power for 2,799 uninterrupted days, breaking the record set by his great uncle Eisaku Sato.

His health has nonetheless been the subject of growing speculation, with reports before his check-up that he had been vomiting blood.

Abe resigned just a year into his first term in 2007, citing his health among other factors. He was diagnosed with ulcerative colitis and spent months undergoing treatment. Upon his return to power, he said he had overcome the illness.

In Japan, even fans of Prime Minister Shinzo Abe want him to step down

The survey conducted over the weekend found 58.4 per cent were unhappy with the government’s handling of the coronavirus.

While Japan has seen a comparatively small outbreak – with nearly 62,000 infections and close to 1,200 deaths – Abe has been slammed for his economic response as well as a widely mocked programme to distribute reusable cloth face masks.

Abe has not held a full-length news conference since mid-June, and has rebuffed opposition calls for a new session of parliament to debate policies for controlling the coronavirus and its economic fallout.

Additional reporting by Reuters, Kyodo, Bloomberg