Fans pose in front of a truck with an advertisement for singer Paul McCartney's 'Out There' tour, after the cancellation of McCartney's concert at the Nippon Budokan in Tokyo on May 20, 2014. Photo: Issei Kato

Music legend Paul McCartney has cancelled his Japan tour because of a debilitating virus that has laid him up in a Tokyo hotel, organisers said on Tuesday, disappointing thousands of the 71-year-old's fans.

McCartney - one of two living members of The Beatles - had already cancelled performances at the National Stadium in Tokyo on Saturday and Sunday, after coming down with the unspecified illness.

He “will regrettably have to cancel the remaining Japanese shows. Paul is still not feeling better and this cancellation is unavoidable,” organiser Kyodo Tokyo said in a statement.

The musician was “staying at a hotel in Tokyo and doctors are with him”, a company spokesperson said, but added that it was “unclear” if he would still perform at a South Korean concert scheduled for May 28.

The cancellation generated an outpouring of good wishes from fans of the Liverpool-born musician.

“Dear Paul, please take care of you! Our hope is only your perfect recovery,” Mari Yamashita wrote in English on the tour's official Facebook page.

McCartney was to play at another venue in Tokyo on Wednesday and the last one in Osaka on Saturday as part of his “Out There” world tour.

In all, McCartney had been expected to play in front of about 170,000 fans in Japan during the four-date tour, according to public broadcaster NHK.

Among McCartney's Tokyo dates was a show at the Nippon Budokan Hall, which would have marked his first return to the venue since appearing there with The Beatles in 1966.

“I was really looking forward to playing in Japan again after we had such an amazing time here in November,” McCartney said in the statement, calling the cancellations “hugely disappointing”.

“I'd like to thank my Japanese fans for their love, messages of support and understanding. I hope to see you all again soon. Love, Paul,” he added.

Concert-goers instead flocked to a downtown Tokyo live music club that plays Beatles tunes, hoping for their fix of The Fab Four.

“Disheartened fans flocked to our club as they wanted to listen to Beatles music,” said Yukihiro Higashi, a manager of Abbey Road Roppongi.

“The cancellations were announced last minute and they didn't know where to go.”

In an earlier tour of Japan in November last year, McCartney belted out 39 songs non-stop without retreating backstage.

Major-selling newspaper the Asahi, citing people familiar with the situation, said McCartney's condition was improving but that he was too unwell to perform on stage.

Organisers were exploring “all possibilities” to reschedule the four-date tour, they said.

The musician flew into Tokyo after a short rest at home in London following a strenuous South America tour.

The Nippon Budokan Hall show had set aside 100 seats for those 25 and under for 1,500 yen ($15) each, the same price as they were 48 years ago when The Beatles played the venue.

The rest of the tickets for the concert, originally scheduled for May 21, were priced at up to 100,000 yen.

Some social media commentary criticised organisers for the sudden cancellation and what they said was a slow refund process.

But Osaka resident Nariaki Shimizu brushed aside the criticism.

“I decided to keep my ticket for (the Osaka concert) without a refund, along with a ticket for the 1980 Nippon Budokan Hall show”, he wrote, referring to an earlier concert that was also cancelled.

In 1980, McCartney was arrested at a Tokyo airport for marijuana possession and was deported. That led to the cancellation of a Japan tour by Wings, the post-Beatles band fronted by McCartney.

A decade later in 1990, the justice ministry gave the green light to McCartney's return for a Japan tour. - AFP