Japan's Prime Minister Yoshihide Suga is seen on a live TV broadcast in Tokyo's Shinjuku area on Thursday, after Japan announced that a virus state of emergency in Tokyo and several other regions will be lifted on June 20. Photo: AFP

Public support for Japanese Prime Minister Yoshihide Suga hit record lows, polls for two major newspapers showed on Monday, turning up the heat on the unpopular premier less than a month before he faces a challenge as leader of the ruling party.

Suga failed to capitalise on delivering the Olympics for the nation stricken by COVID-19, as a fresh wave of infections has forced the government to declare a fourth state of emergency in Tokyo and most urban areas amid a sluggish vaccination rollout. The Mainichi newspaper poll showed public support for Suga slid below 30 percent for the first time, to stand at a dismal 26 percent. The Nikkei daily put his ratings at 34 percent, in line with a record low hit in its survey in July.

One of the polls also showed that Suga's possible rivals for the top job, such as Administrative Reform Minister Taro Kono, who is leading Japan's vaccination push, and former defence minister Shigeru Ishiba, were more popular with the public.

The 72-year-old prime minister also faced rare criticism from writer Haruki Murakami, who said that if the premier was able to see the way out of the pandemic, "He must have very good eyesight for his age."

In a radio appearance on Sunday, the author of the 1987 novel, Norwegian Wood, said, "I'm the same age as Suga, and I don't see a way out.

"That man has ears that don't hear much, but his eyes are exceptionally strong. Or perhaps he just sees what he wants to see." The comments were among the most trending topics on Japanese Twitter. Chief Cabinet Secretary Katsunobu Kato did not comment on the statements at his regular morning news conference.

Both Kono and Ishiba, who have yet to declare if they will run in the Sept. 29 contest, were backed by 16 percent of respondents when asked by the Nikkei who would be the best as the new leader of Suga's Liberal Democratic Party (LDP).

Suga, who has said he would fight to stay in his post, came in fourth at 11 percent, two points behind the low-key former foreign minister Fumio Kishida, 64, who declared his candidacy in a policy speech on Thursday.

The winner is virtually assured of being prime minister because of the LDP's majority in parliament's lower house.

Popularity ratings are being closely watched because the new chief must lead the party to a general election by Nov. 28, but which is expected earlier.